To attain the increase of storing amount of molten metal and the reduction of surface of the molten metal by changing a heating cylinder into a molten metal holding cylinder and changing an injection screw into a plunger provided with an injection head.

The molten metal holding cylinder 11 incorporating the plunger 22 where the injection head 22b is inserted so as to be freely advanced/retreated, is set in a weighing chamber 23 connected with a nozzle hole at the tip part so as to incline the nozzle hole from the horizontal plane at the lower side. A molten metal vessel 15 is concavely arranged at the lower side of the cylindrical body in the lower part from a material charging hole 14 in the molten metal holding cylinder 11. The inner part of the cylindrical body in the upper part from the material charging hole 14 is made to have no space with a closing member 21.