A rotor and a seat mounted on a first shell is disposed between an annular first shell and an annular second shell both constituting a damper case, thereby forming a rotary damper device. A damper lever on which the rotor is mounted is hooked on a fixing pin fixed to a body. Viscous fluid such as highly viscous oil is charged into a damper chamber formed between the rotor and the seat, and a viscous resistance is applied to the rotor and the seat. In a state in which a rotation center of the rotary damper device is deviated from a rotation center of the shaft which is rotated by the operating lever, the damper case is fixed to a flange portion of the shaft, the rotor and the seat are allowed to rotate relatively to each other by an inclining operation of the operating lever, and a resistance force from the rotary damper device is applied to the operating lever.