Provided is a lid device which is compact, and can be installed in an efficient manner. The lid device (20) releasably locks a lid provided with a hinge (12) in a closed position. The lid device is provided with a push lifter that alternates between an extended state and a retracted state each time the lid is pushed, a motor (54) placed next to the push lifter, a lock member (18) and a transmission mechanism (60, 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 perpendicular to each other, and such that the motor at least partly overlaps with the push lifter when seen from the lengthwise direction of the motor.