An electronic component unit and a wire harness include a bus bar plate. The bus bar plate is equipped with a resistor that has a main body and a pair of terminals protruding from the main body, and a substrate main body in which a metallic bus bar is built in a resin material and which has a component mounting section with the resistor mounted thereon. The component mounting section includes a pair of through-holes that penetrates the resin material and the bus bar and allows the terminals to pass, and a recess that is provided between the pair of through-holes, extends in a straight line shape connecting the pair of through-holes, and is capable of supporting the main body of the resistor.