In the present invention, a procedure begins from an operation request received from a communication terminal (50) in step S301, and counting by a timer of a household apparatus (10) begins in step S306. Processes in steps S311-S314 are periodically performed when communication between a controller (30) and a communication adapter (20) is possible. Specifically, the timer of the household apparatus (10) is periodically reset in step S314 so that the timer will not exceed a time limit. However, when communication between the controller (30) and the communication adapter (20) is not performed for some reason, the timer of the household apparatus (10) exceeds the time limit in step S321, and the household apparatus (10) enters a safe operation state in step S322.