To connect a bypass cable simply to the bypass cable joint of an electric apparatus.

In a ground installation type transformer device 11, where the inside of a casing 13 is partitioned into two rooms and in whose one compartment 13a a transformer 15 is accommodated, a secondary charger consisting of the U, V and W phases of the transformer is provided from the front to one side face of the transformer, and connecting conductors 23 are connected individually to each phase of the secondary charger, and also each phase connecting conductor and a low-voltage diverging device 16 for connecting with a distribution line that the transformer has are connected to each other by a connection bar 24, and each phase of connecting conductors connected to the low-voltage diverging device are collected separately for each phase on the side of one side face of the transformer, thereby being provided with the bypass cable joint 20, and connector connecting terminals 26 for connecting connectors 22 attached to bypass cables 21 are set at such positions that they not match one another at each phase in bypass cable joints for each phase, and bypass cables are connected to the connector connecting terminals via the connecting connectors.