A stator of a rotary machine including a rotor, comprising: a ring-shaped stator core formed by coupling a plurality of core segments formed by laminating electrical steel sheets, the core segments including a tooth and a yoke piece; a first insulator made of synthetic resin, the first insulator being mounted on the core segment on a first side in a lamination direction in which the electrical steel sheets are laminated, the first insulator including a first covering portion covering a first end surface of the core segment on the first side in the lamination direction; a second insulator made of synthetic resin, the second insulator being mounted on the core segment on a second side in the lamination direction, the second insulator including a second covering portion covering a second end surface of the core segment on the second side in the lamination direction; and a coil provided to the tooth of the core segment on which the first insulator and the second insulator are mounted, characterized in that; in the core segment, a coupling hole in which the lamination direction is a depth direction is formed in a portion of the yoke piece on a third side in a circumferential direction corresponding to a rotation direction of the rotor, the first insulator includes a first coupling pin protruding toward the second side in the lamination direction, at a portion of the first covering portion on a fourth side in the circumferential direction, and the stator core is formed by coupling the plurality of core segments in a ring shape in a state where the first coupling pin included in the first insulator mounted on the core segment of the core segments adjacent in the circumferential direction that is to the third side in the circumferential direction is inserted in the coupling hole formed in the core segment of the core segments adjacent in the circumferential direction that is to the fourth side in the circumferential direction, and where a side surface on the fourth side in the circumferential direction of the yoke piece in the core segment being to the third side in the circumferential direction and a side surface on the third side in the circumferential direction of the yoke piece in the core segment being to the fourth side in the circumferential direction are in contact with each other. a ring-shaped stator core formed by coupling a plurality of core segments formed by laminating electrical steel sheets, the core segments including a tooth and a yoke piece; a first insulator made of synthetic resin, the first insulator being mounted on the core segment on a first side in a lamination direction in which the electrical steel sheets are laminated, the first insulator including a first covering portion covering a first end surface of the core segment on the first side in the lamination direction; a second insulator made of synthetic resin, the second insulator being mounted on the core segment on a second side in the lamination direction, the second insulator including a second covering portion covering a second end surface of the core segment on the second side in the lamination direction; and a coil provided to the tooth of the core segment on which the first insulator and the second insulator are mounted, characterized in that; in the core segment, a coupling hole in which the lamination direction is a depth direction is formed in a portion of the yoke piece on a third side in a circumferential direction corresponding to a rotation direction of the rotor, the first insulator includes a first coupling pin protruding toward the second side in the lamination direction, at a portion of the first covering portion on a fourth side in the circumferential direction, and the stator core is formed by coupling the plurality of core segments in a ring shape in a state where the first coupling pin included in the first insulator mounted on the core segment of the core segments adjacent in the circumferential direction that is to the third side in the circumferential direction is inserted in the coupling hole formed in the core segment of the core segments adjacent in the circumferential direction that is to the fourth side in the circumferential direction, and where a side surface on the fourth side in the circumferential direction of the yoke piece in the core segment being to the third side in the circumferential direction and a side surface on the third side in the circumferential direction of the yoke piece in the core segment being to the fourth side in the circumferential direction are in contact with each other.