A fixing device includes at least one temperature detector and a device-side connector. The at least one temperature detector is configured to detect a temperature of the fixing device. The device-side connector is configured to transmit a temperature detection signal from the at least one temperature detector to an image forming apparatus body by mutual contact between a terminal of the device-side connector and a terminal of a body-side connector of the image forming apparatus body. A lead wire of the at least one temperature detector is branched into a plurality of wires connected to the device-side connector.