PURPOSE: To accurately and easily detect a change in pressure acting on molten metal in a metal mold cavity, make a structure comparatively simple, and facilitate manufacture and repair.

CONSTITUTION: A deflection quantity transmitting bar 15 whose tip contacts with the reverse of a deflection plate part 13 arranged on a surface of a block 12, is provided, and the deflection quantity transmitting bar 15 is arranged inside the block 12 so as to be slowly movable in the axial direction, and a deflection quantity measuring plate 16 whose outside edge part reverse is supported by a holder in a rear part of the block 12, is arranged in a condition of being pressed against a rear end surface of the deflection quantity transmitting bar 15, and pressurizing casting is performed while measuring molten metal pressure by using a pressure measuring device where a displacement sensor 22 is arranged on the reverse side of the deflection quantity measuring plate 16 and a casting metal mold provided with this pressure measuring device.