A fluid intake/discharge valve body for suction of a cryogenic liquefied gas fluid into a cylinder liner and discharge of the gas fluid with a piston, includes: a valve seat body including a fluid supply portion to supply the fluid and a fluid exhaust portion; an intake valve biased against the fluid supply portion; and a discharge valve biased against the fluid exhaust portion. The fluid supply portion includes a supply pathway connected to a supply pipe; a dividing wall including intake holes facing the intake valve; and a counterbore recessed portion on the dividing wall to surround the intake holes. The intake valve abuts an edge of the recessed portion when biased against the fluid supply portion. The discharge valve receives fluid pressure from a side of the discharge hole including a recessed portion disposed in a region wider than an outer periphery of the discharge hole.