A remote-controlled actuator assembly includes a guide section (3) of an elongated shape, a distal end member (2) fitted to a tip end of the guide section for alteration in attitude, an operating tool (1) in the distal end member, and a restraining tool (6) for aligning the distal end member straight with the guide section. The distal end member is altered in attitude through advancing/retracting attitude altering members (31) in the guide section by attitude altering drive sources (43), which are controlled by an attitude control unit (62). An advance or retraction position detector (45) detects an advance/retraction position of the attitude altering members while the attitude altering members applying a preload to the distal end member restrained by the restraining tool. The attitude control unit uses the detection value as information on the advance/retraction position corresponding to an initial position-attitude of the distal end member.
