Provided is a compressor including a valve unit including: at least two guide pins passing through a discharge valve; and through holes allowing the guide pins to pass therethrough to control oblique motion of the discharge valve with respect to a horizontal direction during up and down movement of the discharge valve. When the discharge valve obliquely moves up and down with respect to the horizontal direction, the guide pin comes into contact with at least two points of an inner circumferential surface of the through hole so that the oblique movement of the discharge valve is restricted, thereby improving the durability of the discharge valve and reducing noise during operation of the compression.