A single-phase induction motor comprises a power consumption prevention device, which includes a current signal transfer element and a switching element. The switching element is turned on/off according to the current signal received from the current signal transfer element. The power consumption prevention device prevents current flow to a start device when the motor runs in normal mode, and thus avoids unnecessary power consumption by the start device when the motor runs in normal mode, thereby preventing a reduction in the efficiency of the single-phase induction motor due to the unnecessary power consumption.