Abstract: A socket attachment structure for attaching a socket to a substrate, the socket including a plurality of contact probes that respectively contact the substrate and a contacted body at both longitudinal direction ends thereof, a probe holder that accommodates and holds therein the plurality of contact probes according to a predetermined pattern, and a holder member provided around the probe holder, includes: a plurality of support members that extend out from a principal plane of the substrate and are respectively inserted through insertion holes provided in the holder member; and a spring member that is attached to the plurality of support members in a state of biasing the holder member placed on the substrate towards the substrate.