A 110V/220V switchable fixing apparatus and a printer therewith including an input voltage detector unit detecting an input voltage of an AC power supply and outputting a signal corresponding to the detected input voltage, a first resistance body having a first end thereof connected to a second terminal of the AC power supply, a second resistance body having a first end thereof connected to a second end of the first resistance body, a first switching unit connected between a second end of the second resistance body and a first terminal to switch on or switch off in response to a control signal from an engine control unit, the engine control unit and a second switching unit connected between the second end of the first resistance body and the second terminal to switch on or switch off in response to the output signal from the input voltage detector unit.