A 3-way switch for a gas-insulated apparatus, comprising: a pressure container having a space part therein, the pressure container including a first connecting part in an upper portion of the space part and a second connecting part in a side portion of the space part such that the second connecting part is perpendicular to the first connecting part; a support conductor provided in the space part, the support conductor having a first guide hole and a second guide hole formed perpendicular to the first guide hole; a disconnecting switch operating part slidably disposed inside the first guide hole, the DS operating part being connected to or separated from the first connecting part by means of an insertion into or extrusion from the first connecting part; an earthing switch operating part slidably disposed inside the second guide hole, the ES operating part being connected to or separated from the second connecting part through an insertion into or protrusion from the second connecting part; a first groove linearly extended from the first guide hole, a first rotatable roller slidably disposed in the first groove and connected to the DS operating part to slidably and linearly move therewith, and a first connecting lever, one end of which is rotatably connected to the first rotatable connecting roller; a second groove linearly extended from the second guide hole, the second groove being perpendicular to the first groove, a second rotatable roller slidably disposed in the second groove and connected to the ES operating part to slidably and linearly move therewith, and a second connecting lever, one end of which is rotatably connected to the second rotatable connecting roller; and a main lever, one end of which is rotatably coupled to the support conductor, and the other end of which is rotatably connected to both the other end of the first connecting lever and the other end of the second connecting lever. a pressure container having a space part therein, the pressure container including a first connecting part in an upper portion of the space part and a second connecting part in a side portion of the space part such that the second connecting part is perpendicular to the first connecting part; a support conductor provided in the space part, the support conductor having a first guide hole and a second guide hole formed perpendicular to the first guide hole; a disconnecting switch operating part slidably disposed inside the first guide hole, the DS operating part being connected to or separated from the first connecting part by means of an insertion into or extrusion from the first connecting part; an earthing switch operating part slidably disposed inside the second guide hole, the ES operating part being connected to or separated from the second connecting part through an insertion into or protrusion from the second connecting part; a first groove linearly extended from the first guide hole, a first rotatable roller slidably disposed in the first groove and connected to the DS operating part to slidably and linearly move therewith, and a first connecting lever, one end of which is rotatably connected to the first rotatable connecting roller; a second groove linearly extended from the second guide hole, the second groove being perpendicular to the first groove, a second rotatable roller slidably disposed in the second groove and connected to the ES operating part to slidably and linearly move therewith, and a second connecting lever, one end of which is rotatably connected to the second rotatable connecting roller; and a main lever, one end of which is rotatably coupled to the support conductor, and the other end of which is rotatably connected to both the other end of the first connecting lever and the other end of the second connecting lever.