12 and accordingly it is possible to prevent the fluid inside the compression chamber 16 from flowing backward into the suction hole 24 fig7 is a front view illustrating a suction valve assembly in accordance with a third embodiment of the present invention in a suction valve 58 in accordance with the second embodiment of the present invention having a fixed portion 60 having a through hole 62 is formed at the center thereof so as to be fixed to the valve seat portion 26 of the piston 12 an open close portion 64 formed at the outside of the fixed portion 60 for performing an opening closing operation of the suction hole 24 and plural neck portions 66 connected between the fixed portion 60 and the open close portion 66 herein the plural neck portions 66 are radially connected through space portions 68 formed by cutting portions between the fixed portion 60 and the open close portion 64 it is preferable to form four neck portions 66 and the number of neck portions can be adjusted according to a pressure of the fluid fig8 is a front view illustrating a suction valve assembly in accordance with a third embodiment of the present invention in a suction valve 70 in accordance with the third embodiment of the present invention having a fixed portion 72 is formed at the center so as to be fixed to the valve seat portion 26 of the piston 12 an open close portion 74 formed at the outside of the fixed portion 72 for performing opening closing operation of the suction hole 24 and plural neck portions 76 connected between the fixed portion 72 and the open close portion 74 and a guide groove 78 is formed.