PURPOSE: To keep a sterilization of liquid medicine and to shorten a time for filling by closing a vacuum suction circuit and opening a liquid medicine supply circuit so as to fill the liquid medicine into a vacant chamber of an outer cylinder after evacuating that vacant chamber by opening the vacuum suction circuit and closing the liquid medicine supply circuit.

CONSTITUTION: A gasket 6 made of rubber is screwed to a plunger rod 5 inserted through an opening 4 of an outer cylinder 2. That gasket 6 is fitted liquid-tightly to the inner face of outer cylinder 2 and freely movable lengthwise. Therefore, if the liquid medicine is filled after setting the tip face 7 of the gasket 6 at a position lcorresponding to a specified volume, the specified volume of liquid medicine can be filled. When the outer cylinder 2 is communicated with a vacuum suction circuit 10, however, pressure inside the outer cylinder becomes negative, the gasket 6 is sucked toward a tip face 8 of inner chamber and there is a fear that the position l can be kept no more. It is possible, therefore, to keep the specified gasket 6 position l by arranging a stopper 21, which has a cross-sectional shape of U and a length corresponding to the position l, between the head 19 of plunger rod and a brim part 20 of the outer cylinder 2.