Abstract: A continuous current type power factor correction circuit in a power device having rectifying means for rectifying an alternating current, a booster converter having an inductor, a diode and a capacitor series connected to an output terminal of the rectifying means, a control switch connected in parallel with the series connection of the diode and capacitor, and a load connected across the capacitor for outputting a boosted direct current to the load according to switching operation of the control switch, and a power factor correction circuit controlling the switching operation of the control switch, the power factor correction circuit, comprising; an off-time controller comparing a first voltage signal with a second voltage signal and generating an off signal in response to the comparison, an on-time controller generating an on signal in accordance with a charge time period of the capacitor, the charge time period being determined from a point in time wherein the off-time controller generates the off signal,