A terminal block for a vehicle-mounted battery assembly, the terminal block being attached to a total positive/negative terminal block which is attached to the vehicle-mounted battery assembly. An external extraction positive-side fastening portion and an external extraction negative-side fastening portion are positioned at different heights. A terminal cover is configured to cover the external extraction positive-side fastening portion. The terminal cover includes a fitting portion fitted into the terminal block for the vehicle-mounted battery assembly, a hinge portion engaged with the fitted portion, an arm portion engaged with the hinge portion, and a cover body engaged with the arm portion. The arm portion has a predetermined length, so that by hinge operation of the hinge portion, the cover body covers both the external extraction positive-side fastening portion and the external extraction negative-side fastening portion which are positioned at different heights.