PURPOSE: To obtain a DC circuit for power converter in which a branch line can be provided without increasing the width of bus bar.

CONSTITUTION: A pair of bus bars 1, 2 are arranged in parallel through an insulating board 3 and a stud 4 standing on the bus bar 1 is inserted into the holes 2a, 3a of the insulating board 3 and the bus bar 2. On the other hand, a branch wire 8 is fixed to the forward end of the stud 4 covered with a tubular insulating cap 9. The insulating board 3 is stopped at a first protrusion 9a of the insulating cap 9 interposed between the bus bar 2 and the insulating board 3. The insulating cap 9 is prevented from falling off the bus bar 2 by means of a second protrusion 9b provided on the opposite side to the insulating board 3 of the bus bar 2.