Provided is a lid device which is compact, and can be installed in an efficient manner. The lid device (20) releasably locks a lid (10) provided with a hinge (12) in a closed position. The lid device is provided with a push lifter (32) that alternates between an extended state and a retracted state each time the lid is pushed, a motor (46) placed next to the push lifter, a lock member (18) and a transmission mechanism (64) for transmitting the output of the motor. The push lifter and the motor are arranged such that a lengthwise direction of the push lifter and a lengthwise direction of the motor are parallel to each other.