To not only insulate an operator of electric works performing hot-line jobs on a high-voltage charging line but also protect the operator from arc burns and further protect the occipital part and the neck part of the operator who is conventionally defenseless from electric shocks and the arc burns.

The flame-retardant insulation clothes are composed by interposing a fire-resisting layer on the right surface or back surface or in the middle of a flame-retardant layer formed of a cloth made of flame-retardant fibers such as aramid, locating an insulating layer formed of a multilayered insulating film on the inside thereof, and applying a flame-retardant lining fabric without any sense of incompatibility. The flame-retardant insulating clothes are tailored to design a guard mountable on an electric safety hat capable of covering the occipital part and neck part of the operator.