A connection/disconnection control device for controlling the connection/disconnection of a motive power transmission path by supplying a working fluid of a specified pressure to a connection/disconnection mechanism is provided with a valve for opening and closing a flow channel for the working fluid and an open/close detection unit for detecting the openness of the valve. A malfunction-detecting device of the connection/disconnection control device is provided with a valve open/close control unit, a clock unit for counting a specified period from the start of an open/close operation, and a malfunction-detecting unit for determining that the connection/disconnection control device is malfunctioning when counting is completed without the detection results of the open/close detection unit matching the control details from the open/close control unit.