The connector structure selectively uses either a UTP connector or an STP connector. The UTP connector includes UTP connection terminals connected to respective electric wires of a UTP cable and a UTP dielectric having a pair of housing portions in which the UTP connection terminals are housed. The STB connector includes STP connection terminals connected to respective electric wires of an STP cable and an STP dielectric having a pair of housing portions in which the STP connection terminals are housed. In the UTP dielectric, at least a partition wall for partitioning the pair of housing portions is made of a material having a relatively high dielectric constant. In the STP dielectric, at least a partition wall for partitioning the pair of housing portions is made of a material having a relatively low dielectric constant.