PURPOSE: To prevent an infrared ray due to an exogenous parameter from being fetched as a data signal by discriminating whether or not a received signal is from a remote controller prior to fetching the data signal.

CONSTITUTION: The discrimination is made whether or not a signal from the remote controller 1 is received. When it is received, contents of a judgement checking signal are compared with those of a set code. If they are equal, a data code with respect to the data signal is fetched. Where the fetched data is correct, the number of data fetching times is counted. If it is one, a moved member 5 is operated to lock a door. When it is not one, the door is opened. If the fetched data is not correct, the number of fetching times is discriminated. When it exceeds the set number of times, the set time is locked to stop the fetching of data only during the set time.