A good mating state can be obtained while reducing interference of transmission signals by a simple configuration. A contact portion is provided at a single location on each of mating recessed portions of signal contact members arranged in a multipolar shape, contact portions are provided at a plurality of locations for a mating recessed portion of an integrated power-source contact member, and signal transmission is carried out through the single-location contact portion provided at the single location for each of the mating recessed portions of the signal contact members. As a result, particularly, interference in high-frequency transmission is reduced to obtain good transmission characteristics, while sufficient mating retention force is configured to be obtained by causing the contact portions at the plurality of locations provided on the mating recessed portion of the power-source contact member to be in a state in which the contact portions are in contact with contact portions of a mating counterpart by the plurality of locations.