Abstract: A heater control apparatus for use with a plurality of printers each having a heater, comprises a detection part for detecting occurrence of zero crossing of a voltage signal supplied from a power supply and for supplying a zero cross signal each time the zero crossing is detected, a signal part for detecting an ON state of a request signal, the request signal being turned ON when a heater of any of the plurality of printers is currently turned ON, a first control part for determining a delay time in accordance with a predetermined device number setting value such that a timing with which a heat-on signal is supplied to a heater of a subject printer lags by the determined delay time behind a timing with which the zero cross signal is supplied by the detection part, and a second control part for supplying a heat-on signal to the heater of the subject heater at a timing defined by the determined delay time only when the request signal is turned OFF, thereby preventing two or more heaters from being turned ON si