of the disk portion 702 in a certain length the connecting portion 703 of the vibration transfer member 700 may be coupled to the sub frame 620 and a certain space may be formed between the vibration transfer member 700 and the sub frame 620 a second compressing unit may be provided at the vibration transfer member 700 so as to compress gas by using vibration transferred through the vibration transfer member 700 the second compressing unit and the first compressing unit may be positioned on the same line particularly the second compressing unit may be disposed at a rear side of the first piston 640 so as to accelerate sucking of the refrigerant into the suction passage 643 that is formed in the first piston 640 of the first compressing unit by using the vibration of the second compressing unit the second compressing unit may include a second piston 710 fixedly coupled to the vibration transfer member 700 so as to be located between the vibration transfer member 700 and the sub frame 620 a second cylinder 720 into which the second piston 710 is inserted a support frame 730 coupled to the second cylinder 720 a second discharge valve assembly c 2 mounted at one side of the second cylinder 720 so as to control discharging of the refrigerant and a second suction valve 740 mounted at the end.