PURPOSE: To increase the degree of freedom of selection of forming liquid and to perform remote control by stable pressure adjustment by putting liquid in the pump supply liquid pressure dome of a liquid pressure forming device in an oil pressure cylinder by ascent of a piston resisting adjusted oil pressure.

CONSTITUTION: Liquid pressure forming liquid 2 is supplied from a pump 3 to the liquid tank 1a of a liquid pressure dome 1 to a specified height through a check valve, and a blank B is placed. When an upper die descends and formes the blank B, the liquid 2 passes through a pipe 5 and enters the lower chamber 61 of an oil pressure cylinder 6, and a piston 6a is raised by discharge of pressure oil from a pressure regulating valve 10 regulated by a control amplifier 11 of the upper chamber 62 and gives specified pressure to the liquid 2. After forming, the piston 6a is lowered by applying oil pressure by a change-over valve 8 and pushes out a formed product. Water or rust preventing liquid etc., can be selected freely as the forming liquid 2, and pumps of small size and small capacity are enough for the purpose, and stable remote pressure regulation can be made by the control amplifier 11. In figure, S1, S2 are limit switches of the height of the piston 6a.