To reduce the installation space while simplifying the installation by housing equipment such as an earth transformer, a neutral compensation reactor, a neutral resistor, a disconnector, and the like, is the same steel box and interconnecting them in the box.

An earth transformer 7, a neutral resistor 10, a neutral compensation reactor 15, and disconnectors 11, 16 are housed in a neutral point earthing unit steel box 20 and the equipment are interconnected electrically in the neutral point earthing unit box 20. According to the arrangement, the installation space of a neutral point earthing unit can be reduced, the installation can be simplified and the installation schedule can be shortened.