PROBLEM TO BE SOLVED: To provide an injector having a structure for applying physical energy to a percussion cap for favorably combusting the percussion cap.SOLUTION: The injector includes a drive mechanism for plunging a striker 4 into the percussion cap. The drive mechanism includes: an energizing part for energizing the striker toward the percussion cap from a time of preparing for injection of injection solution till plunging the striker 4 into the percussion cap a holding part that, when preparing for the injection, holds the striker 4 so as to locate at a preparation position separated from the percussion cap by the energizing force of the energizing part an attitude retention part that retains the attitude of the striker 4 with respect to the percussion cap when the striker 4 approaches to the percussion cap and a movement part that moves the striker to a first position where the holding by the holding part is released, and then, moves the striker 4, by energizing force of the energizing part, to a second position where the attitude retention by the attitude retention part is started.
