An inverter device of a rotating electrical machine drives a multiphase rotating electrical machine having the variable number of rotations using a switching element provided for each phase. An example of the inverter device of the rotating electrical machine includes: a frequency setting unit for determining and setting a carrier frequency of a carrier signal for use in driving the switching element for each phase depending on the state of each phase of the rotating electrical machine for each specified electrical angle obtained by equally dividing a cycle of an electrical angle; and a signal generation unit for generating a drive signal for drive of the switching element of each phase using the carrier signal of the carrier frequency set for each phase by the frequency setting unit. The carrier frequency of each phase is an integral multiple of the phase voltage frequency at the specified electrical angle.