To satisfy a target power cycle life by reducing the load factor of an inverter module, improving the capacity of a cooling fin and a cooling fan, and inhibiting the increase in temperature since the inverter module repeats temperature change every time when it repeats operation and stop and hence wiring bonding in the inverter module reaches rupture due to the thermal deterioration of materials when the inverter is built into a system for frequently repeating the operation and stop of a load motor, and since the power cycle life of an inverter module is affected by temperature change.

This inverter device stops the cooling fan, reduces cooling capacity for inhibiting the temperature decrease in the power module, and enters a next operation without decreasing temperature fully to minimize the temperature change in the power module, extends a power cycle life, reduces the load factor of the inverter module, and satisfies the target power cycle life even if the capacity of the cooling fin and the cooling fan is not increased.