Injecting device

The invention discloses an injecting device for the medical field. The injecting device comprises an external sleeve, a needle holder and a mandrel, wherein a first limiting seat and a second limiting seat are arranged in an internal circle of the external sleeve, and a fixing ring is arranged between the first limiting seat and the second limiting seat; the needle holder comprises a needle holder main body, a needle holder sleeve and a needle holder pedestal; a clamping device is arranged in the internal circle of the needle holder main body; the bottom of the needle holder pedestal is contacted with the top of the fixing ring in a face to face way; the mandrel comprises a mandrel head which is fixed through the clamping device after injecting; when the injecting device is subject to self destruction, a radial pressure and an axial friction force from the fixing ring are brought to the needle holder, so that the portability that the injecting device is stirred up due to error operation. Compared with the pri