A control device (7, 35) to control an inverter (2, 22, 27) for driving an electric motor (1, 21, 26), comprising: an acquirer (4b, 4a, 32a, 32b, 4c) to acquire a DC voltage input to the inverter (2, 22, 27), an output voltage of the inverter (2, 22, 27), a motor amperage of a current flowing through the electric motor (1, 21, 26), and a motor frequency indicating a rotation rate of the electric motor (1, 21, 26); a loss calculator (5, 33) to calculate a stator loss and a rotor loss including fundamental losses and harmonic losses of the electric motor, based on at least one of the DC voltage, the output voltage of the inverter (2, 22, 27), the motor amperage, and the motor frequency; and a controller (4, 32) to output an actual control value for control of the inverter (2, 22, 27), based on the output voltage of the inverter (2, 22, 27), the stator loss and the rotor loss, wherein the loss calculator (5, 33) calculates: the stator loss comprising a fundamental primary copper loss, a harmonic primary copper loss, a stator fundamental iron loss and a stator harmonic iron loss of the electric motor (1, 21, 26); and the rotor loss comprising a fundamental secondary copper loss, a harmonic secondary copper loss and a stator harmonic iron loss of the electric motor (1, 21, 26); the fundamental primary copper loss of the electric motor based on an effective value of the motor amperage of the current flowing through the electric motor (1, 21, 26); the harmonic primary copper loss, the stator fundamental iron loss and the stator harmonic iron loss, based on the output voltage of the inverter (2, 22, 27) and the motor frequency; the fundamental secondary copper loss based on the DC voltage, the output voltage of the inverter (2, 22, 27), the motor amperage and the motor frequency; and the harmonic secondary copper loss and a rotor harmonic iron loss based on the output voltage of the inverter (2, 22, 27) and the motor frequency. an acquirer (4b, 4a, 32a, 32b, 4c) to acquire a DC voltage input to the inverter (2, 22, 27), an output voltage of the inverter (2, 22, 27), a motor amperage of a current flowing through the electric motor (1, 21, 26), and a motor frequency indicating a rotation rate of the electric motor (1, 21, 26); a loss calculator (5, 33) to calculate a stator loss and a rotor loss including fundamental losses and harmonic losses of the electric motor, based on at least one of the DC voltage, the output voltage of the inverter (2, 22, 27), the motor amperage, and the motor frequency; and a controller (4, 32) to output an actual control value for control of the inverter (2, 22, 27), based on the output voltage of the inverter (2, 22, 27), the stator loss and the rotor loss, wherein the loss calculator (5, 33) calculates: the stator loss comprising a fundamental primary copper loss, a harmonic primary copper loss, a stator fundamental iron loss and a stator harmonic iron loss of the electric motor (1, 21, 26); and the rotor loss comprising a fundamental secondary copper loss, a harmonic secondary copper loss and a stator harmonic iron loss of the electric motor (1, 21, 26); the fundamental primary copper loss of the electric motor based on an effective value of the motor amperage of the current flowing through the electric motor (1, 21, 26); the harmonic primary copper loss, the stator fundamental iron loss and the stator harmonic iron loss, based on the output voltage of the inverter (2, 22, 27) and the motor frequency; the fundamental secondary copper loss based on the DC voltage, the output voltage of the inverter (2, 22, 27), the motor amperage and the motor frequency; and the harmonic secondary copper loss and a rotor harmonic iron loss based on the output voltage of the inverter (2, 22, 27) and the motor frequency. the stator loss comprising a fundamental primary copper loss, a harmonic primary copper loss, a stator fundamental iron loss and a stator harmonic iron loss of the electric motor (1, 21, 26); and the rotor loss comprising a fundamental secondary copper loss, a harmonic secondary copper loss and a stator harmonic iron loss of the electric motor (1, 21, 26); the fundamental primary copper loss of the electric motor based on an effective value of the motor amperage of the current flowing through the electric motor (1, 21, 26); the harmonic primary copper loss, the stator fundamental iron loss and the stator harmonic iron loss, based on the output voltage of the inverter (2, 22, 27) and the motor frequency; the fundamental secondary copper loss based on the DC voltage, the output voltage of the inverter (2, 22, 27), the motor amperage and the motor frequency; and the harmonic secondary copper loss and a rotor harmonic iron loss based on the output voltage of the inverter (2, 22, 27) and the motor frequency.