There is provided an insulating material including a composite resin material comprising an organic resin and minute particles containing a metal element. The organic resin includes a resin material including polyester as a main backbone thereof and having an alkoxy group. The minute particles have an average particle size of greater than or equal to 0.5 nm but less than or equal to 50 nm. Such an insulating material is used as an insulating layer of a wiring member (wiring board, covered electric wire, etc.) including a conductor and the insulating layer which covers the conductor.