A vale unit includes a valve frame and two valve plates. The valve frame defines a valve opening. The valve plates are formed with protrusions. Each of the valve plates has a connecting end that is formed with a notch. The connecting ends are connected to each other. The protrusions protrude from peripheries of the notches. Each of the protrusions has a contact end. The contact ends cooperatively define a gap therebetween. The valve plates are co-rotatable about an axis between a closed position, in which the valve plates substantially close the valve opening, and an opening position, in which the valve plates open the valve opening. The gap has a width varying in response to co-rotation of the valve plates between the opening position and the closed position.

A reciprocating compressor includes a shell, a driving motor, a drive shaft, a piston, a cylinder, a valve plate, a suction valve, and a suction valve stopper. The suction valve stopper is made of an elastic member and disposed between the suction valve and the cylinder to support a reed valve portion of the suction valve and limit an opening amount of the reed valve portion. The opening amount is controlled to increase cooling power in a high load operation area and prevent dead volume to thereby increase energy efficiency in a low load operation area and a high load operation area.