An electrophotographic image forming apparatus includes a device to set a temperature correspondence electrifying duty ratio relative to a fixing heater of a fixing device according to a detected temperature of the fixing device. A device is included to set a power corresponding electrifying duty ratio relative to the fixing heater, according to a detected voltage of the commercial power source. A device is additionally included to compare the temperature correspondence electrifying duty ratio and the power correspondence electrifying duty ratio. When the temperature correspondence electrifying duty ratio is equal to or larger than the power correspondence electrifying duty ratio, it is restricted with the power correspondence electrifying duty ratio to obtain a restricted electrifying duty ratio. Electrifying control relative to the fixing heater is then performed using the restricted ratio. When electrifying the fixing heater immediately after the power has been turned on, a power correspondence electrifying duty ratio is set according to a first voltage and electrifying control is performed relative to the fixing heater using the power correspondence electrifying duty ratio set according to the first voltage.