Disclosed is a double-casing frame of an electric machine that is cooled by a fluid circulating in the fluid circulation space (26) inside the double casing, said double-casing frame comprising: an inner casing (22) on which an end flange (30) is mounted at the rear of the machine; and an outer casing (24) that fits over the inner casing (22) and can be separated from the inner casing (22) without removing the end flange (30).