SEAL STRUCTURE

PROBLEM TO BE SOLVED: To provide a seal structure preventing the occurrence of sliding between a seal material and a shaft, and facilitating the attachment and removal of the seal material.SOLUTION: This seal structure comprises: a housing 10 comprising first and second housings 11, 12 and in which a through-hole 14 penetrating through the first and second housings 11, 12 is formed; a shaft 2 inserted through the through-hole 14; and an elastically deformable annular seal material 3 which is mounted around the shaft 2, which is held by being in press contact with an outer circumferential surface of the shaft 2 and each of inner circumferential surface parts of the through-hole 14 at the first and second housings 11, 12, and which is housed in the housing 10 in the elastically deformed state. A clearance space 16 allowing the elastic deformation of the seal material 3 accompanying the reciprocal movement of the shaft 2 along an axial direction is formed between the shaft 2 and the housing 10. The seal material 3 is deformable so that a contact surface thereof with the shaft 2 during the reciprocal movement of the shaft 2 is moved together with the shaft 2.