diff --git a/.idea/farmitry_hvac.iml b/.idea/farmitry_hvac.iml
index ef0ceff..16e3543 100644
--- a/.idea/farmitry_hvac.iml
+++ b/.idea/farmitry_hvac.iml
@@ -131,6 +131,7 @@
     <orderEntry type="library" scope="PROVIDED" name="rubocop-rails-omakase (v1.1.0, rbenv: 3.4.2) [gem]" level="application" />
     <orderEntry type="library" scope="PROVIDED" name="ruby-progressbar (v1.13.0, rbenv: 3.4.2) [gem]" level="application" />
     <orderEntry type="library" scope="PROVIDED" name="rubyzip (v2.4.1, rbenv: 3.4.2) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="rufus-scheduler (v3.9.2, rbenv: 3.4.2) [gem]" level="application" />
     <orderEntry type="library" scope="PROVIDED" name="securerandom (v0.4.1, rbenv: 3.4.2) [gem]" level="application" />
     <orderEntry type="library" scope="PROVIDED" name="selenium-webdriver (v4.31.0, rbenv: 3.4.2) [gem]" level="application" />
     <orderEntry type="library" scope="PROVIDED" name="smart_properties (v1.17.0, rbenv: 3.4.2) [gem]" level="application" />
diff --git a/Gemfile b/Gemfile
index d2e30ce..c671f92 100644
--- a/Gemfile
+++ b/Gemfile
@@ -71,3 +71,4 @@ end
 
 gem "ccutrer-serialport"
 gem "rmodbus"
+gem "rufus-scheduler"
diff --git a/Gemfile.lock b/Gemfile.lock
index 8c08f76..61ec0e2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -294,6 +294,8 @@ GEM
       rubocop-rails (>= 2.30)
     ruby-progressbar (1.13.0)
     rubyzip (2.4.1)
+    rufus-scheduler (3.9.2)
+      fugit (~> 1.1, >= 1.11.1)
     securerandom (0.4.1)
     selenium-webdriver (4.31.0)
       base64 (~> 0.2)
@@ -382,6 +384,7 @@ DEPENDENCIES
   rails (~> 8.0.2)
   rmodbus
   rubocop-rails-omakase
+  rufus-scheduler
   selenium-webdriver
   solid_cable
   solid_cache
diff --git a/app/services/modbus/polling_service.rb b/app/services/modbus/polling_service.rb
index 310c513..710705f 100644
--- a/app/services/modbus/polling_service.rb
+++ b/app/services/modbus/polling_service.rb
@@ -1,56 +1,41 @@
+# polling_service.rb
+require "rufus-scheduler"
+
 module Modbus
   class PollingService
     class << self
       def start
-        return if $modbus_polling_threads.any?(&:alive?)
-        $modbus_polling_threads << start_thread
-      end
+        return if defined?(@scheduler) && @scheduler&.running?
 
-      def stop
-        $modbus_polling_threads.each { |t| t.kill if t.alive? }
-        $modbus_polling_threads.clear
-        puts "Modbus polling service 중지됨"
-      end
+        puts "[#{Time.current}] Modbus polling service 시작됨 (Rufus)"
+        @scheduler = Rufus::Scheduler.new
 
-      def running?
-        $modbus_polling_threads.any?(&:alive?)
-      end
-
-      private
-      def start_thread
-        Thread.new { run_polling_loop }
-      end
-
-      def run_polling_loop
-        puts "Modbus polling service 시작됨"
-        last_logged = nil
-
-        loop do
-          begin
-            now = Time.now
-            current = [ now.hour, now.min ]
-            current_time = format("%02d:%02d", current[0], current[1])
-            puts "# current time: #{current_time}.#{now.sec}"
-            if current != last_logged
-              puts "시간 변경 감지됨: #{current_time}"
-              schedule = Schedule.find_by(hour: current[0], minute: current[1])
-              apply_schedule(schedule) if schedule
-              last_logged = current
-            end
-            sleep 1
-          rescue => e
-            puts  "[#{Time.current}] #{file} 에러: #{e.message}"
-          end
+        @scheduler.cron "0 * * * * *" do
+          now = Time.now
+          current_time = format("%02d:%02d", now.hour, now.min)
+          puts "# current time: #{current_time}.#{now.sec}"
+          schedule = Schedule.find_by(hour: now.hour, minute: now.min)
+          apply_schedule(schedule) if schedule
         end
       end
 
+      def stop
+        @scheduler&.shutdown
+        puts "[#{Time.current}] Modbus polling service 중지됨"
+      end
+
+      def running?
+        @scheduler&.running?
+      end
+
+      private
       def apply_schedule(schedule)
         if schedule.is_active
           run_script("on_off.rb", "0", "[Schedule] ON")
           run_script(
             "serial.rb",
             (schedule.temperature * 10).to_i.to_s,
-            "[Schedule] #{schedule.hour}:#{schedule.minute} → #{schedule.temperature}°C"
+            "[Schedule] #{format('%02d:%02d', schedule.hour, schedule.minute)} → #{schedule.temperature}°C"
           )
         else
           run_script("on_off.rb", "1", "[Schedule] OFF")