A detection substrate 150 has a body film 1a having a through hole 91; a winding wire part 10 provided on a surface of one side of the body film 1a, on a surface of another side of the body film 1a and in the through hole 91, and disposed so as to surround a current to be detected; and a winding return wire part 50, provided on the body film 1a, connected at a terminal end part of the winding wire part 10 and returning from the terminal end part toward a starting end part side.