A driving circuit for a single-phase-brushless motor, includes: a driving-signal-generating circuit to generate a driving signal for supplying, to a driving coil of the single-phase-brushless motor, first- and second-driving currents, alternately with a de-energized period therebetween during which neither of the first or the second driving current is supplied to the driving coil; an output circuit to supply the first or the second driving current to the driving coil in response to the driving signal; and a zero-cross detecting circuit to detect a zero cross of an induced voltage, generated across the driving coil, during the de-energized period, wherein the driving-signal-generating circuit determines a length of a subsequent energized period based on a driving cycle from a start of an energized period, during which the output circuit supplies the first or the second driving current to the driving coil, to a time when the zero-cross-detecting circuit detects the zero cross.