A remote controlled actuator assembly which comprises: a spindle guide section of an elongated shape; a distal end member fitted to a tip end of the spindle guide section through a distal end member connecting unit for alteration in attitude; a tool rotatably provided in the distal end member; a tool rotation drive source for rotating the tool; and an attitude altering drive source for operating the attitude of the distal end member, the attitude altering drive source including a rotary actuator; in which the distal end member rotatably supports a spindle for holding the tool, in which the spindle guide section has its interior accommodating a rotary shaft for transmitting a rotation of the tool rotation drive source to the spindle and a guide hole having its opposite ends opening, and in which a flexible attitude altering member is reciprocally movably inserted within the guide hole, and has a tip of the attitude altering member for undergoing a reciprocating or retracting motion in contact with the distal end member so as to alter the attitude of the distal end member about an axis perpendicular to a longitudinal axis of the spindle, the attitude altering member being selectively advanced or retracted by the attitude altering drive source; the remote controlled actuator assembly further comprising: a motion converter mechanism (44 B) configured to reduce a speed of input rotation from the attitude altering drive source and configured to convert-its rotational output to advance or retraction motion and then to output it, and an output member having a contact portion that contacts the base end of the attitude altering member, the contact portion being operable to advance or retract according to an output of the motion converter mechanism, thereby, in turn, causing the attitude altering member to advance or retract; wherein the motion converter mechanism includes a worm that is rotated by rotation of the attitude altering drive source and a worm wheel that is in mesh with the worm, and wherein the worm wheel forms said output member having the contact portion that slidingly contacts the attitude altering member and is operable to cause the attitude altering member to advance or retract. a spindle guide section of an elongated shape; a distal end member fitted to a tip end of the spindle guide section through a distal end member connecting unit for alteration in attitude; a tool rotatably provided in the distal end member; a tool rotation drive source for rotating the tool; and an attitude altering drive source for operating the attitude of the distal end member, the attitude altering drive source including a rotary actuator; in which the distal end member rotatably supports a spindle for holding the tool, in which the spindle guide section has its interior accommodating a rotary shaft for transmitting a rotation of the tool rotation drive source to the spindle and a guide hole having its opposite ends opening, and in which a flexible attitude altering member is reciprocally movably inserted within the guide hole, and has a tip of the attitude altering member for undergoing a reciprocating or retracting motion in contact with the distal end member so as to alter the attitude of the distal end member about an axis perpendicular to a longitudinal axis of the spindle, the attitude altering member being selectively advanced or retracted by the attitude altering drive source; the remote controlled actuator assembly further comprising: a motion converter mechanism (44 B) configured to reduce a speed of input rotation from the attitude altering drive source and configured to convert-its rotational output to advance or retraction motion and then to output it, and an output member having a contact portion that contacts the base end of the attitude altering member, the contact portion being operable to advance or retract according to an output of the motion converter mechanism, thereby, in turn, causing the attitude altering member to advance or retract; wherein the motion converter mechanism includes a worm that is rotated by rotation of the attitude altering drive source and a worm wheel that is in mesh with the worm, and wherein the worm wheel forms said output member having the contact portion that slidingly contacts the attitude altering member and is operable to cause the attitude altering member to advance or retract. a motion converter mechanism (44 B) configured to reduce a speed of input rotation from the attitude altering drive source and configured to convert-its rotational output to advance or retraction motion and then to output it, and an output member having a contact portion that contacts the base end of the attitude altering member, the contact portion being operable to advance or retract according to an output of the motion converter mechanism, thereby, in turn, causing the attitude altering member to advance or retract; wherein the motion converter mechanism includes a worm that is rotated by rotation of the attitude altering drive source and a worm wheel that is in mesh with the worm, and wherein the worm wheel forms said output member having the contact portion that slidingly contacts the attitude altering member and is operable to cause the attitude altering member to advance or retract.