A fixing device includes a fixing member, a pressure member, a separation claw which is provided so as to be contactable on a surface of the fixing member and comes into contact with the surface of the fixing member to separate the recording medium from the fixing member at a fixing operation and a moving mechanism which moves the separation claw in a rotational axis direction of the fixing member. The moving mechanism includes a thrust gear having a protrusion on the lower surface of the thrust gear and a thrust cam disposed below the thrust gear having a hole on the upper surface into which the protrusion can be fitted when the fixing device is assembled.