A connection terminal structure includes a substrate having one surface and including a pad formed on the one surface, a bonding part constituted by a solder, and a connection terminal having first and second ends and including a fixing part formed on the first end and a connection part formed on the second end. The fixing part includes a first surface that is bonded to the pad by way of the bonding part. The connection terminal includes a pad facing surface that faces the pad and includes the first surface. The connection terminal includes at least one groove that is formed in the pad facing surface. The at least one groove extends from the first surface to the connection part. A portion of the solder that constitutes the bonding part fills in the at least one groove.