PURPOSE: To generate an adequate frequency command at the moment of power returning after an instantaneous stoppage of an inverter and prevent an error in restarting.

CONSTITUTION: In an instantaneous stoppage restarting method for an inverter, an adequate frequency command at the moment of power-return is obtained under restarting control using a deceleration pattern from a free run state to a stop state of the motor after the instantaneous stoppage of the motor (M). A condition discriminating circuit 7 for generating a discrimination signal (S0) that activates the deceleration pattern (P) is provided between an instantaneous stoppage detecting means 6 for detecting the stoppage, and a frequency calculation control circuit 2A for receiving a frequency command signal (f) for frequency calculation. When the discrimination signal (S0) is received, the frequency calculation control circuit 2A stores the revolution at the occurrence of instantaneous stoppage on the basis of the deceleration pattern and controls the frequency so that the motor (M) can returns to the stored frequency at the moment of power-return.