A wiring board (3) has first and second rigid sections (11, 12) each having six metal leaf layers, and a flexible section (13) having two metal leaf layers that connect the both rigid sections (11, 12). A capacitor unit (34) and a filter unit 31, which supplies power to an inverter, are mounted on the first rigid section (11), and a CPU (21) and a pre-driver circuit element (22) are mounted on the second rigid section (12). Mutually-independent two control systems are arranged so as to be symmetrical about a board center line (M). Detection signal lines (51) of rotation sensors (37, 38) located at the middle of the first rigid section (11) extend along the board center line (M) on the flexible section (13). Each of the two control systems is configured along a wiring direction of the detection signal lines (51).