An on-vehicle device operation apparatus according to an embodiment includes an operation part, an on-vehicle device control part, and a display control part. The operation part is provided in an inside of a vehicle and includes a plurality of operation switches. When one of the operation switches is pushed, the on-vehicle device control part controls an on-vehicle device depending on the pushed operation switch. The display control part causes a display part to display an image corresponding to the operation part. when a first operation switch with no assigned operation among the plurality of operation switches is pushed, the display control part causes the display part to emphatically display a portion corresponding to the first operation switch in the image corresponding to the operation part.