A fixing device includes a heating rotating body that heats a developer image formed on a recording medium, a pressurizing rotating body that pressurizes the recording medium by nipping the recording medium between the pressurizing rotating body and the heating rotating body, a pair of support plates that rotatably support both ends of one of the pressurizing rotating body and the heating rotating body, and a release member including an attachment portion attached to the support plates to hold the support plates from both sides in a thickness direction, and an operating portion. When an external force in a predetermined direction acts on the operating portion, the release member releases pressing of the one of the pressurizing rotating body and the heating rotating body against the other by moving the support plates in a direction away from the other.