To improve the efficiency of assembly work by performing inserting and fixing of a circuit breaker unit in one direction of a box-shaped body.

A metal-enclosed switch gear includes: a box-shaped body 1 housing an electrical device; a pair of guides 10a and 10b that extend from the front surface side to the back surface side of the box-shaped body 1 and is fixed on the side wall; a circuit breaker units 4a and 4b having a draw-out type circuit breaker that moves on the pair of guides 10a and 10b; and bolts 5a and 5b that are fixing means for fixing the circuit breaker units 4a and 4b to the box-shaped body 1. Insertion work of the circuit breaker units 4a and 4b and fixing work by the bolts 5a and 5b can be performed from the front surface side.