A medical manipulator (10, 200) comprising: a handle (16, 218); a shaft (18, 216) extending from the handle (16, 218); a distal-end working unit (14, 214) having an end effector (12, 212), the distal-end working unit (14, 214) being operatively coupled to the shaft (18, 216) for being tilted with respect to the shaft (18, 216) and rolled; and operating means (21, 221) disposed between the handle (16, 218) and the distal-end working unit (14, 214), the operating means (21, 221) having a portion extending into the distal-end working unit (14, 214) for acting on the end effector (12, 212); wherein the distal-end working unit (14, 214) has a rotor (56, 230) rotatable about a roll axis in unison with the end effector (12, 212), the rotor (56, 230) having a hollow tube, and a rotational support tube (58, 232) having a posture variable with respect to an axial direction of the shaft (18, 216), the rotor (56, 230) being rotatably supported by an inner circumferential surface of the rotational support tube (58, 232); the rotor (56, 230) has a circumferentially extending annular groove (56d, 320) defined in an outer circumferential surface thereof; characterized in that the rotational support tube (58, 232) has at least one side hole (71, 354) extending through a wall thereof between inside and outside surfaces thereof, with an engaging member (72, 335) disposed in the side hole (71, 354); and the engaging member (72, 335) is fixed to the rotational support tube (58, 232) while an inner end (72b, 335b) of the engaging member (72, 335) is inserted in the circumferentially extending annular groove (56d, 320). a handle (16, 218); a shaft (18, 216) extending from the handle (16, 218); a distal-end working unit (14, 214) having an end effector (12, 212), the distal-end working unit (14, 214) being operatively coupled to the shaft (18, 216) for being tilted with respect to the shaft (18, 216) and rolled; and operating means (21, 221) disposed between the handle (16, 218) and the distal-end working unit (14, 214), the operating means (21, 221) having a portion extending into the distal-end working unit (14, 214) for acting on the end effector (12, 212); wherein the distal-end working unit (14, 214) has a rotor (56, 230) rotatable about a roll axis in unison with the end effector (12, 212), the rotor (56, 230) having a hollow tube, and a rotational support tube (58, 232) having a posture variable with respect to an axial direction of the shaft (18, 216), the rotor (56, 230) being rotatably supported by an inner circumferential surface of the rotational support tube (58, 232); the rotor (56, 230) has a circumferentially extending annular groove (56d, 320) defined in an outer circumferential surface thereof; characterized in that the rotational support tube (58, 232) has at least one side hole (71, 354) extending through a wall thereof between inside and outside surfaces thereof, with an engaging member (72, 335) disposed in the side hole (71, 354); and the engaging member (72, 335) is fixed to the rotational support tube (58, 232) while an inner end (72b, 335b) of the engaging member (72, 335) is inserted in the circumferentially extending annular groove (56d, 320).