A fixing device includes a fixing rotary body, a heat shield movably disposed opposite the fixing rotary body, an opposed body contacting the fixing rotary body to form a nip therebetween through which a recording medium is conveyed, and a temperature detector to detect a temperature of at least one of the fixing rotary body and the opposed body. A controller, operatively connected to the heat shield and the temperature detector, determines a rotation angled position to which the heat shield is moved based on a size of the recording medium and the temperature of the at least one of the fixing rotary body and the opposed body detected by the temperature detector.