A material pressure feeding apparatus 10 includes a sack 11 containing material M having predetermined viscosity, a container 12 for holding the sack 11, a press member 13 disposed within the container 12 and positioned on the sack 11, a pressure feeder 15 having a suction port 37A for sucking the material M for lowering the press member 13 to pressurize the sack 11 containing the material M. Thepress member 13 includes a plate 21 having a plane-shape substantially identical to the opening 19 of the container 12, and a tubular member 22 along the inner peripheral side surface of the container 12, hanging vertically from the outer periphery of the plate 21 and forms a reception space 23. The press member 13 descends to reduce the volume of sack 11 forming wrinkled portion S and the wrinkled portion S is settled in the reception space 23.