To provide a fan motor drive in which cooling mode can be switched depending on presence/absence of a control signal being inputted externally.

In the fan motor drive 100, a smoothing circuit 10 smoothes a pulse width modulated control signal CNT for controlling the r.p.m. of a fan motor and outputs a first control voltage Vcnt1. A second control voltage generating section 20 outputs a temperature dependent second control voltage Vcnt2 for controlling the r.p.m. of the fan motor. Based on the comparison results of the first control voltage Vcnt1 and a predetermined reference voltage Vref, a selecting section 30 judges presence/absence of a control signal CNT being inputted externally and outputs any one of the first and second control voltages Vcnt1 and Vcnt2 selectively. A drive control section 40 drives the fan motor 110 based on the output from the selecting section 30.