The assemblability of LA terminals with electric wires is improved. The electric wires of the main wiring lines of a precharge circuit are laid on the front surface of a base plate, LA terminals connected to the electric wires are clamped to the relay terminal portions of a main relay mounted on the rear surface, by screws together with main-circuit bus bars, each of the LA terminals has a wing portion protruded beyond the protuberant height of an electric-wire connection portion, an electric wire is bent and disposed to extend from the front surface side of the base plate toward the relay terminal portion, a terminal accommodation portion in which the LA terminals are accommodated is provided at a part extending from the electric-wire bent portion to the relay terminal portion, and bottomed grooves into which the wing portions are inserted are formed in the terminal accommodation portion.