PURPOSE: To provide a pressurizing device using water power which is available to a vegetable squeezer or the like by taking city water as a power source in an instrument in which a tubular expansive body is housed in a bag made of a fiber.

CONSTITUTION: There is a bellows-shaped expansive body B2 which aimes at pressurization with water power in the inside bottom part of a main body A, pressured water to be poured is filled in the inside through the water conducting port of the bellowsshaped expansive body B2 when a water valve in the bottom part of a cylinder is opened, the bellows is expanded in the cylinder, a matter 7 to be compressed is pressurized/compressed and vegetable juice is squeezed. Thus, the matter 7 to be compressed is gathered in the vicinity of the opening in the upper part of the cylinder, so it is favorable to take out a dewatered matter. When water-pouring into the bellows-shaped expansive body B2 is again continued in the state that the cover is removed, the ascending expansion of the bellows-shaped expansive body B2 is continued to the allowable expansion limit and the matter 7 to be compressed is automatically pushed out.