Toward the development of an in-wheel drive system, we propose an integrated printed circuit board (PCB) structure with low inductance and high cooling performance from direct oil-cooling. This structure consists of a PCB as the main circuit board and a power module to shorten the current path and the heat dissipation path. In addition, snubber capacitors using ceramic capacitors are mounted on the PCB to expand the mutual inductance between a positive current path and a negative current path. The resulting structure demonstrated a low inductance of 9.9 nH and low thermal resistance of 29 mm2K/W.