Electronic circuit board and electronic circuit device

An electronic circuit device for driving and controlling an actuator, comprising:

• a case;
• and
• an electronic circuit board accommodated in the case, and having a multilayer printed wiring board, wherein the electronic circuit board includes:
• a first component mounting part on which an electronic component for power system is mounted and a second component mounting part on which an electronic component for control system is mounted;
• a flexible part located between the two component mounting parts, formed to have a thickness thinner than that of each of boards of the component mounting parts so as to have flexibility higher than that of each of the component mounting parts, and provided with a conductive wire electrically connecting between the two component mounting parts;
• and a dummy pattern provided at a position closer to an outer edge of the flexible part than the conductive wire, in the flexible part,
• wherein the electronic circuit board is accommodated in the case in a state in which the flexible part is bent and deformed such that the first component mounting part and the second component mounting part are superposed to each other,
• wherein the dummy pattern extends to each wiring layer of a plurality of wiring layers of the component mounting parts, the plurality of wiring layers extending through and being the same as those of the flexible part so as to the dummy pattern intersects borders in a plan view between the component mounting parts and the flexible part,
• wherein the multilayer printed wiring board making up the component mounting parts and the flexible part is formed by laminating layers of base materials each of which is provided with a metal foil layer on one or both surfaces of a corresponding one layer of the layers of the base materials,
• wherein the flexible part has a pair of recessed grooves formed by removing at least one wiring layer of the plurality of wiring layers on an outermost side in the flexible part, and
• wherein the base materials of the component mounting parts and the flexible part extend continuously.