A fixing device including: arms that support the heating roller and the pressure roller so as to be displaced between a pressure-contact attitude in which a nip portion is formed and a distanced attitude in which the nip portion is released; a solenoid that displaces the rollers to the distanced attitude; a separation plate that has an electric conductivity, is disposed to face the heating roller, and separates the sheet that has passed through the nip portion from the heating roller; and interlocking arms that, in interlock with displacement from the pressure-contact attitude to the distanced attitude by the solenoid, displace a first end portion of the separation plate to an attitude to be distanced away from the heating roller by a first distance, change the potential of the separation plate from a floating potential to a reference potential, and accelerate discharge between the heating roller and the separation plate.