Gas insulated electrical apparatus and method of manufacturing gas insulated electrical apparatus

A method of manufacturing a gas insulated electrical apparatus, the method comprising:

• preparing a container filled with insulating gas, a high voltage conductor located inside the container and applied with a prescribed voltage, and an insulating support member configured to insulate and support the high voltage conductor relative to the container, the insulating support member including electrical, thermal, or shock insulation;
• and
• covering the high voltage conductor by a first dielectric film,
• the first dielectric film including a first main surface exposed inside the container, and a second main surface located on a side opposite to the first main surface and being in contact with the high voltage conductor, and
• the first dielectric film being provided with a first through hole extending from the first main surface to the second main surface, the method further comprising:
• forming a first coating film on an inner circumferential surface of the first through hole such that at least a hole diameter of the first through hole is less than a diameter of an electron avalanche.