To provide an inverter device wherein a frequency command inputted from an external controller can be simply and immediately increased or decreased by pressing down a key on a built-in operation panel or turning a rotary switch and this frequency command (the running speed of a loading apparatus) can be appropriately adjusted according to the present operational status of the loading apparatus.

The inverter device includes: a power circuit 19 for driving a motor 20; a control circuit portion 1 for controlling the power circuit 19; the operation panel 12 for setting data for operating conditions; and a frequency command selector 2 for inputting a frequency command from the external controller 17. The inverter device is provided with an increasing/decreasing device 4 for increasing or decreasing an inputted frequency command by pressing the key on the operation panel or turning the rotary switch.