A division type mechanical seal in which a stationary sealing ring provided on the side of a housing or a rotating sealing ring provided in a rotation shaft which is inserted into the housing is a divided sealing ring divided in the circumferential direction, the division type mechanical seal that does sealing by sealing end faces (4a, 7a) serving as opposing end faces of the stationary sealing ring and the rotating sealing ring, the division type mechanical seal comprising: a through hole portion formed over two divided sealing rings (12, 13) so as to go over divided contact faces (12a, 13a) of the two divided sealing rings (12, 13) adjacent to each other in the circumferential direction; and a coupling tool inserted into the through hole portion to couple the two adjacent divided sealing rings (12, 13), characterized in that: the coupling tool includes a bolt, a nut if no female screw portion is formed in the through hole portion in one of the two divided sealing rings, and a tube fitted to a shaft portion of the bolt, there is no gap on the inner diameter side of the tube but there is a gap on the outer diameter side of the tube when the coupling tool is inserted into the through hole portion, and the tube is compressible in an axial direction of the tube and is preliminarily formed in a shape to be easily expandable in an outer diameter direction of the tube in the vicinity of a center in the axial direction when the two adjacent divided sealing rings (12, 13) are coupled by either fastening the nut or, if a female screw portion is formed in the through hole portion in one of the two divided sealing rings, by fastening the bolt. a through hole portion formed over two divided sealing rings (12, 13) so as to go over divided contact faces (12a, 13a) of the two divided sealing rings (12, 13) adjacent to each other in the circumferential direction; and a coupling tool inserted into the through hole portion to couple the two adjacent divided sealing rings (12, 13), characterized in that: the coupling tool includes a bolt, a nut if no female screw portion is formed in the through hole portion in one of the two divided sealing rings, and a tube fitted to a shaft portion of the bolt, there is no gap on the inner diameter side of the tube but there is a gap on the outer diameter side of the tube when the coupling tool is inserted into the through hole portion, and the tube is compressible in an axial direction of the tube and is preliminarily formed in a shape to be easily expandable in an outer diameter direction of the tube in the vicinity of a center in the axial direction when the two adjacent divided sealing rings (12, 13) are coupled by either fastening the nut or, if a female screw portion is formed in the through hole portion in one of the two divided sealing rings, by fastening the bolt. the coupling tool includes a bolt, a nut if no female screw portion is formed in the through hole portion in one of the two divided sealing rings, and a tube fitted to a shaft portion of the bolt, there is no gap on the inner diameter side of the tube but there is a gap on the outer diameter side of the tube when the coupling tool is inserted into the through hole portion, and the tube is compressible in an axial direction of the tube and is preliminarily formed in a shape to be easily expandable in an outer diameter direction of the tube in the vicinity of a center in the axial direction when the two adjacent divided sealing rings (12, 13) are coupled by either fastening the nut or, if a female screw portion is formed in the through hole portion in one of the two divided sealing rings, by fastening the bolt.