To provide an injector of which the collar part and grip pieces are prevented from being damaged and which is user-friendly.

In the injector (1), the collar part (4) is formed at a main body (2), a punctuation member (3) is formed in a projecting manner below the collar part (4), and the grip pieces (5) having buffering parts (9) and holding means (8) are mounted to both of the sides of the collar part (4). Regarding each grip piece (5), the holding means (8) is extended from the collar part (4) through the buffering part (9), and a grip support part (7) and a grip end (6) are extended from the holding means (8), and the collar part (4) is spaced away from the holding means (8).