A connection member electrically connects an optical element configured to convert an electric signal to an optical signal or to convert an optical signal to an electric signal, a first substrate including an incident/releasing port of an optical transmission path for an optical signal at least one end portion thereof, and a second substrate to each other. The optical transmission path is optically coupled with the optical element to transmit the optical the connection. The connection member includes a connection unit connected to the second substrate and a holding unit having elasticity and holding the first substrate. The holding unit is provided with an electrode at a connecting position to the first substrate, and the holding unit holds the first substrate by connecting the first substrate to the electrode.