Loose connectors connecting electric devices increase electromagnetic radiation. Previous studies indicate that loose connectors inherently increase inductance and resistance at connection contact boundaries, and such increased inductance is a dominant factor in increasing the intensity of electromagnetic radiation especially when devices work in high-frequency bands. In this paper, to investigate the mechanism of increased inductance at loose connector contact boundaries, we compute the value of current density at contact points and the strength of the magnetic field in the area around the connector cross section. Our simulation results show that current curves along the circumferential directions of a cable due to loose connectors. Extended current paths resulting from that bypass current arise sectionally, and the effect of the bypass current can be regarded as the main factor in increasing inductance. We also clarify an increased inductance trend arising from loose connectors based on the length of the noncontact areas in the contact boundary surface.