An electronic component unit includes a plate made of a resin material configured to embed metallic bus bars in the resin material and mount electronic components thereon, and a supporting member to which the plate is assembled. The plate has a plurality of exposed ends at which the bus bars are partially exposed on edge surfaces of the plate. The supporting member includes protrusions that are formed on opposed surfaces facing the edge surfaces of the plate such that the protrusions face the edge surfaces of the plate, protrude from the opposed surfaces toward the edge surface sides of the plate, and are each located between the adjacent exposed ends in an arrangement direction of the multiple exposed ends.