To make a metering chamber and moldings thereof smaller to thereby reduce the amount of resin used for the moldings.SOLUTION: A method of manufacturing a metering chamber 52 includes the steps of: supplying resin to two dies of an injection molding machine, the first die being used to injection-mold a first intermediate molding, which is a front surface of the metering chamber, and the second die being used to injection-mold a second intermediate molding, which is a back surface of the metering chamber 52； moving the first die and the second die relatively such that the first intermediate molding faces the second intermediate molding, and then crimping the first intermediate molding and the second intermediate molding together to form a panel-shaped third intermediate molding with the front surface and the back surface of the metering chamber 52 joined together； and supplying resin along an outer periphery of the joint between the first intermediate molding and the second intermediate molding in the third intermediate molding, to thereby seal the outer periphery.SELECTED DRAWING: Figure 5【課題】計量チャンバーとその成型体を小型化し、計量チャンバーの成型に用いられる樹脂の使用量を低減する。【解決手段】計量チャンバー５２の製造方法は、射出成型機の２つのダイに樹脂を供給し、第１のダイにおいて計量チャンバーの表面側となる第１の中間成形体を射出成型し、第２のダイにおいて計量チャンバー５２の裏面側となる第２の中間成形体を射出成型する工程と、第１のダイと第２のダイを相対的に移動させて第１の中間成形体と第２の中間成形体を互いに対向させ、第１の中間成形体と第２の中間成形体を互いに合わせて圧着し、計量チャンバー５２の表面側と裏面側を合わせたパネル状の第３の中間成形体を成形する工程と、第３の中間成形体における第１の中間成形体と第２の中間成形体を互いに合わせた部分の外周に沿って樹脂を供給し、当該外周を封止する工程と、を有する。【選択図】図５
