diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Revision history for pms-application-service
 
+## 0.1.3.0 -- 2026-07-05
+
+* Fixed the configuration setting loading process.
+
 ## 0.1.2.0 -- 2026-05-31
 
 * Added pms-infra-agent-socket, pms-infra-agent-serial.
diff --git a/pms-application-service.cabal b/pms-application-service.cabal
--- a/pms-application-service.cabal
+++ b/pms-application-service.cabal
@@ -20,7 +20,7 @@
 -- PVP summary:     +-+------- breaking API changes
 --                  | | +----- non-breaking API additions
 --                  | | | +--- code changes with no API change
-version:            0.1.2.0
+version:            0.1.3.0
 
 -- A short (one-line) description of the package.
 synopsis:           pms-application-service
diff --git a/src/PMS/Application/Service/App/Control.hs b/src/PMS/Application/Service/App/Control.hs
--- a/src/PMS/Application/Service/App/Control.hs
+++ b/src/PMS/Application/Service/App/Control.hs
@@ -68,7 +68,12 @@
               , DM._allowedAgentCmdsDomainData = conf^.agentAllowedCmdsConfigData
               , DM._sandboxNetworksDomainData  = conf^.sandboxNetworksConfigData
               , DM._invalidPatternsDomainData  = conf^.invalidPatternsConfigData
-              , DM._timeoutMicrosecDomainData = conf^.timeoutMicrosecConfigData
+              , DM._timeoutMicrosecDomainData =
+                  -- Use the value from YAML if present; otherwise fall back to the
+                  -- default (30 seconds) defined in DomainData.defaultDomainData.
+                  maybe (defDom ^. DM.timeoutMicrosecDomainData)
+                        id
+                        (conf ^. timeoutMicrosecConfigData)
               }
 
       appDat = def {
diff --git a/src/PMS/Application/Service/DM/Type.hs b/src/PMS/Application/Service/DM/Type.hs
--- a/src/PMS/Application/Service/DM/Type.hs
+++ b/src/PMS/Application/Service/DM/Type.hs
@@ -52,7 +52,7 @@
   , _agentAllowedCmdsConfigData :: [String]
   , _sandboxNetworksConfigData  :: [String]   -- ^ CIDR list for agent-socket-open
   , _invalidPatternsConfigData  :: [String]   -- ^ regex blacklist for write commands
-  , _timeoutMicrosecConfigData :: Int
+  , _timeoutMicrosecConfigData :: Maybe Int  -- ^ If absent in YAML, falls back to the default in DomainData.defaultDomainData (30 seconds).
   } deriving (Show, Read, Eq)
 
 makeLenses ''ConfigData
@@ -99,7 +99,8 @@
       , _agentAllowedCmdsConfigData = def   -- deny all by default
       , _sandboxNetworksConfigData  = def   -- deny all by default
       , _invalidPatternsConfigData  = def   -- allow all by default
-      , _timeoutMicrosecConfigData = 30 * 1000 * 1000
+      , _timeoutMicrosecConfigData = Nothing
+      -- Default value (30 seconds) is owned by DomainData.defaultDomainData.
       }