PROBLEM TO BE SOLVED: To provide a stern tube seal device in which a liner can be mounted to a propeller shaft easily and which comprises seal rings capable of withstanding for a long life, and provide a ship equipped with the same.SOLUTION: A stern tube seal device 1 comprises: a liner 19 which is externally fitted to a propeller shaft connected to a propeller that is mounted to a stern of a ship; and a plurality of seal rings 11 arranged at different shaft-direction positions in a shaft direction of the propeller shaft so as to slide-contact with the outer peripheral surface of the liner. The liner includes: a heat conduction part 19a5 in contact with the outer peripheral surface of the propeller shaft at least in the shaft-direction position of each seal ring; and a gap formation part 19a2 for forming a gap between the outer peripheral surface of the propeller shaft and the liner, which is provided at least in one part of a region other than the heat conduction part in the shaft direction.
