A remote-controllable toy includes a controller (2) for transmitting a code signal in accordance with the content of operation by a user, a drive device (1) driven/controlled according to the code signal, and an extension unit (10) detachably attached to the controller (2). The extension unit (10) has code signal acquisition means (31 51 52) for acquiring the code signal output from the controller (2) and processing execution means (30, 61) for judging the state of the drive device (1) according to the code signal acquired and executing a predetermined processing based on the judgment result.