A cryostat for electric power conditioner comprising external walls (1, 3, 11) in contact with an ambient medium, internal walls (2, 12, 13) in contact with a cooled medium and a thermal insulating gap (4, 14) formed between the external walls (1, 3, 11) and the internal walls (2, 12, 13). At least one part of the at least one external wall (1, 3, 11) and/or at least one part of the at least one internal wall (2, 12, 13) of the cryostat comprises a layered structure (15, 16, 17).