One embodiment provides a circuit board having a substrate and an electrode portion which is provided on the substrate. The electrode portion includes: a quadrangular land which is provided on a front surface of the substrate; a solder layer which is laminated on the whole of a front surface of the land; and a pad which is joined to a front surface of the solder layer. When the electrode portion is seen from thereabove, an outer circumferential line of the pad touches each of four sides of the land. Exposed portions where the solder layer is exposed are formed individually at four corners of a front surface of the electrode portion. And, the exposed portions are formed to have the same shape.