A circuit board includes a plate-shaped dielectric body with a first and a second main surface and including a first area not to be bent and a second area to be bent such that the first main surface becomes an outer side, a first reinforcing member located in the first area nearer the first main surface in relation to a center of the second area in a thickness direction and away from the second area, and a second reinforcing member located in the first area nearer the second main surface in relation to the center of the second area and contacting with a border between the first and the second areas. The first main surface curves from an edge of the first reinforcing member closest to the second area, and the second main surface curves from an edge of the second reinforcing member on the border.