A stepping motor drive device includes: a first pulse generation circuit that generates pulses at rising or falling edges of a first clock signal; a second pulse generation circuit that generates pulses at rising and falling edges of a second clock signal; a first mask circuit that outputs or masks the output of the first pulse generation circuit depending on whether the second clock signal is normal; a second mask circuit that outputs or masks the output of the second pulse generation circuit depending on whether the first clock signal is normal; a logic circuit that logically combines the outputs of the mask circuits; a step position control circuit that determines the step position of a motor according to the output of the logic circuit; and a motor drive section that supplies a current to the motor according to the output of the step position control circuit.