Fixing device and image forming apparatus

A fixing device comprising:

• a pressure applying unit that is provided facing a heating unit,
• wherein the pressure applying unit includes
• an endless belt-shaped member that rotates by being driven by rotation of the heating unit, and
• a retainer that retains the endless belt-shaped member in a movable manner,
• wherein the retainer has an upstream adjuster that is located at an upstream side of the retainer with respect to a rotational direction of the endless belt-shaped member and that has a curved shape with a center, in a longitudinal direction of the retainer, which is a most bulging area from which the upstream adjuster decreases in height toward opposite ends of the upstream adjuster in the longitudinal direction, and
• wherein the upstream adjuster is separated from the heating unit such that no point along the endless belt-shaped member is simultaneously contacted by the upstream adjuster and the heating unit.