A connector for a medical instrument connected to an external device for medical use, comprising: a plug portion in which a plurality of electric contact point portions (31, 33) to the external device are placed; and an outer sheath case (23, 24) connectively provided at the plug portion; a sub frame member interposed between the plug portion and the outer sheath case (23, 24), and having a flange portion which abuts on respective end portions of the plug portion and the outer sheath case (23, 24), wherein the sub frame member is a disk-shaped metal frame; a main frame member comprising a ring member fixed to the distal end thereof, said main frame member housed in the outer sheath case (23, 24) and fixed to the sub frame member; characterised in that the connector comprises: a first fixing member adapted to fix the outer sheath case (23, 24) to the main frame by fastening such that the outer sheath case (23, 24) is pressed in a longitudinal axis direction of the main frame, wherein the first fixing member is a fastening ring providing a compression force by being screwed to the ring member; and a second fixing member adapted to fasten the plug portion.to the flange portion, wherein the second fixing member consists of three fixing screws for fixing the sub frame member via receiving pipes, wherein the outer sheath case (23, 24) receives reaction force to compression force generated in the longitudinal axis direction of the main frame by being butted against the flange portion by fastening of the first fixing member and is fixed to the main frame and the sub frame member in a state in which the outer sheath case (23, 24) is compressed, and the plug portion receives pressure generated by being butted against the flange portion by fastening of the second fixing member, and is fixed to the sub frame member in a state in which the plug portion is compressed. a plug portion in which a plurality of electric contact point portions (31, 33) to the external device are placed; and an outer sheath case (23, 24) connectively provided at the plug portion; a sub frame member interposed between the plug portion and the outer sheath case (23, 24), and having a flange portion which abuts on respective end portions of the plug portion and the outer sheath case (23, 24), wherein the sub frame member is a disk-shaped metal frame; a main frame member comprising a ring member fixed to the distal end thereof, said main frame member housed in the outer sheath case (23, 24) and fixed to the sub frame member; characterised in that the connector comprises: a first fixing member adapted to fix the outer sheath case (23, 24) to the main frame by fastening such that the outer sheath case (23, 24) is pressed in a longitudinal axis direction of the main frame, wherein the first fixing member is a fastening ring providing a compression force by being screwed to the ring member; and a second fixing member adapted to fasten the plug portion.to the flange portion, wherein the second fixing member consists of three fixing screws for fixing the sub frame member via receiving pipes, wherein the outer sheath case (23, 24) receives reaction force to compression force generated in the longitudinal axis direction of the main frame by being butted against the flange portion by fastening of the first fixing member and is fixed to the main frame and the sub frame member in a state in which the outer sheath case (23, 24) is compressed, and the plug portion receives pressure generated by being butted against the flange portion by fastening of the second fixing member, and is fixed to the sub frame member in a state in which the plug portion is compressed. a first fixing member adapted to fix the outer sheath case (23, 24) to the main frame by fastening such that the outer sheath case (23, 24) is pressed in a longitudinal axis direction of the main frame, wherein the first fixing member is a fastening ring providing a compression force by being screwed to the ring member; and a second fixing member adapted to fasten the plug portion.to the flange portion, wherein the second fixing member consists of three fixing screws for fixing the sub frame member via receiving pipes, wherein the outer sheath case (23, 24) receives reaction force to compression force generated in the longitudinal axis direction of the main frame by being butted against the flange portion by fastening of the first fixing member and is fixed to the main frame and the sub frame member in a state in which the outer sheath case (23, 24) is compressed, and the plug portion receives pressure generated by being butted against the flange portion by fastening of the second fixing member, and is fixed to the sub frame member in a state in which the plug portion is compressed.