An exhaust diffuser includes: an internal cylinder; an external cylinder that forms an exhaust passage between the internal cylinder and the external cylinder, the exhaust passage expanding from front to rear; and at least one tubular strut that couples the internal cylinder and the external cylinder together. The external cylinder includes: a front conical portion that is positioned forward of the tubular strut; and an outer flaring portion that starts flaring at a positon forward of the tubular strut at an inclination angle that is greater than an inclination angle of the front conical portion. The internal cylinder includes: a front straight portion that faces the front conical portion and the outer flaring portion; and an inner flaring portion that starts flaring at a position between a maximum width portion and a trailing edge of the tubular strut.