An inverter apparatus according to one embodiment includes switching elements and freewheel diodes which are connected to a direct-current power supply, a temperature detector provided near at least one of the switching elements, and a temperature estimation unit. The temperature estimation unit estimates temperatures of switching elements not provided with the temperature detector, based on an estimated-temperature increase value calculated by a loss model of the switching elements and freewheel diode and others, and a temperature of the switching element detected by the temperature detector.