A fixing device includes a fixing rotary body and a pressing member each of which includes a waveform elastic layer having at least one wave crest and at least one wave trough to form a waveform face between the fixing rotary body and the pressing member pressed against each other. A controller identifies a temperature differential between a first temperature of the wave crest of the fixing rotary body detected by a first temperature detector and a second temperature of the wave trough of the fixing rotary body detected by a second temperature detector and adjusts an amount of heat stored from a heater into the fixing rotary body based on the identified temperature differential.