An electronic apparatus includes a main body and an optional device detachably connected thereto via two connectors each having multiple signal terminals corresponding to various signals. The main body includes a connection confirmation unit that confirms that a specific signal terminal in the multiple signal terminals of each connector is connected; a request-signal generating unit that sends a request signal from the main body to the optional device via a signal terminal other than the specific signal terminal when connection of the specific signal terminal is confirmed by the connection confirmation unit, and requests a reply signal from the optional device; and a communication confirmation unit that determines that the two connectors of the main body and the optional device are connected when confirming that the reply signal is received via the signal terminal other than the specific signal terminal.