PROBLEM TO BE SOLVED: To accurately administer a liquid medicine by applying a liquid medicine administration apparatus in intracorporeally administering insulin.SOLUTION: When a piston 21 is moved to a maximum pressure position, a distal end of the piston 21 is moved to a position to be flush with a bottom surface of a flow passage 22B or a position being not the flush position but a position inside the flow passage 22B. Thus, when an air bubble exists in an internal space 22A, the air bubble existing in the internal space 22A is pushed out into the flow passage 22B with the use of a distal end surface of the piston 21 when the piston 21 is moved to the maximum pressure position. Consequently, a probability to draw back the air bubble into the internal space 22A when the piston 21 is subsequently moved to a draw back position is extremely reduced.COPYRIGHT: (C)2013,JPO&INPIT【課題】本発明は、精度よく薬液を投与する。【解決手段】本発明は、ピストン21を押切位置に移動させる際、該ピストン21の先端が流路22Bの底面と同一平面上となる位置又は該位置よりも流路22B内の位置まで移動させるので、内部空間22Aに気泡が存在した場合、ピストン21が押切位置に移動する際に内部空間22Aに存在する気泡を該ピストン21の先端面で流路22B内に押し出すことができるので、その後にピストン21が引戻位置に移動される際に気泡を再び内部空間22A内に引戻す可能性を大幅に減少させることができる。【選択図】図5
