An image forming apparatus that has a normal mode and a power saving mode in which power consumption is reduced as compared with the normal mode and that returns to the normal mode when a predetermined return condition is satisfied in the power saving mode, the image forming apparatus comprising: a fixing portion that includes a fixing member which receives power supply so as to increase in temperature and that fixes an image printed on a sheet to the sheet with the fixing member whose temperature is increased to a predetermined temperature; a temperature detection portion that receives power supply so as to output a voltage corresponding to a temperature of the fixing portion; a power supply portion that performs the power supply to the fixing portion and the temperature detection portion in the normal mode and that stops the power supply to the fixing portion and the temperature detection portion in the power saving mode; a control portion that detects, based on the output of the temperature detection portion, the temperature of the fixing portion so as to perform temperature control on the fixing portion and that returns the image forming apparatus to the normal mode by performing predetermined return processing including fixing return processing in which when the return condition is satisfied, the temperature of the fixing portion is increased to the predetermined temperature; wherein the control portion detects, when the return condition is satisfied, the temperature of the fixing portion based on the output of the temperature detection portion, and when the detected temperature of the fixing portion is high, the control portion starts the fixing return processing at later timing than when the detected temperature is low, characterized by a photovoltaic module that receives light so as to generate electric power; and a power storage/supply portion that stores the power output from the photovoltaic module and that performs power supply to the temperature detection portion when the power supply from the power supply portion to the temperature detection portion is stopped. a fixing portion that includes a fixing member which receives power supply so as to increase in temperature and that fixes an image printed on a sheet to the sheet with the fixing member whose temperature is increased to a predetermined temperature; a temperature detection portion that receives power supply so as to output a voltage corresponding to a temperature of the fixing portion; a power supply portion that performs the power supply to the fixing portion and the temperature detection portion in the normal mode and that stops the power supply to the fixing portion and the temperature detection portion in the power saving mode; a control portion that detects, based on the output of the temperature detection portion, the temperature of the fixing portion so as to perform temperature control on the fixing portion and that returns the image forming apparatus to the normal mode by performing predetermined return processing including fixing return processing in which when the return condition is satisfied, the temperature of the fixing portion is increased to the predetermined temperature; wherein the control portion detects, when the return condition is satisfied, the temperature of the fixing portion based on the output of the temperature detection portion, and when the detected temperature of the fixing portion is high, the control portion starts the fixing return processing at later timing than when the detected temperature is low, characterized by a photovoltaic module that receives light so as to generate electric power; and a power storage/supply portion that stores the power output from the photovoltaic module and that performs power supply to the temperature detection portion when the power supply from the power supply portion to the temperature detection portion is stopped.