To provide a shaft seal structure to enable sealing firmly even in a part having a high pressure difference and free from defects such as damage.

A shaft seal member body 22 is provided around the shaft of the rotary shaft 1 in the peripheral direction. An expansion chamber formed in the rotary shaft 1, labyrinth fins, and floating rings having fine gap to the outer periphery of the rotary shaft 1 arranged in the peripheral direction are provided alternately in the shaft direction on the inner peripheral surface of the shaft seal member body 22. An accommodating groove 37 is formed on the inner peripheral surface of the shaft seal member body. Support springs 33 which protrude to the outer peripheral side, disposed in the accommodating groove 37 and absorb the force pressing to the side faces of the accommodating groove 37 by elastic deformation are provided to the floating rings along 26 the peripheral direction.