Replacement method and replacement programfor for treatment mechanism in treatment apparatus

Disclosed is a method for replacing a process instrument in a processing apparatus, in which a target object is loaded by transfer mechanism into a processing unit and is subjected to a process by use of the process instrument. The method includes confirming that a process on the target object is finished in a processing unit designated as a process instrument replacement target, and providing information that a process instrument replacing operation is permitted to start. The method further includes, when a shutter of the processing unit designated as the process instrument replacement target is closed to perform a process instrument replacing operation and an operation prohibition state is thereby applied to the transfer mechanism, canceling the operation prohibition state to allow the transfer mechanism to perform a load/unload operation relative to a processing unit not designated as a process instrument replacement target.