The present invention provides a structure for protecting a corner of a case of an inverter (an on-board device), and provides the structure for protection having improved assembling efficiency. The present Description discloses the structure for protecting a corner of a case of an inverter. The structure includes a protector for covering the corner, and a receiving portion provided on the case. The protector is fixed at least at two points arranged on a straight line on a first surface adjacent to the corner. The receiving portion is provided on a second surface adjacent to the corner. The receiving portion is provided at a position where the receiving portion receives an edge of the protector when the protector rotates around a straight line Pv passing through at least two fixed points.