A remote controlled actuator includes a spindle guide section (3) of an elongated configuration, a distal end member (2) fitted to a tip end of the spindle guide section for alteration in attitude, and a drive unit housing (4a) to which a base end of the spindle guide section is connected. The distal end member rotatably supports a spindle (13) then holding a tool (1). The spindle guide section includes a hollow outer shell pipe (25), a rotary shaft (22) and a guide pipe (30), and an attitude altering member (31) for altering an attitude of the distal end member is inserted within the guide pipe. A hollow (24) of the outer shell pipe includes a round hole portion (24a) at a center and a grooved portion (24b) depressed radially outwardly from the round hole portion. The rotary shaft is arranged within the round hole portion whereas the guide pipe is arranged within the grooved portion.