An electronic circuit device includes a lower-side substrate formed with a main circuit; an upper-side substrate formed with a drive control circuit that drivingly controls the main circuit; a support body positionally fixed above the lower-side substrate with resin in a hardened state; and a case having a peripheral portion with an outer surface that has at least a portion of an external lead-out terminal of the drive control circuit and the main circuit thereon, and a substrate storage space that accommodates the lower-side substrate on a side inward from the peripheral portion.