A turning device S provided at a joint of a robot arm 2 includes: a shaft cover 7 including a tubular wall 70 extending in an axial direction Da； a turning shaft 9 inserted into an inside of the wall 70 of the shaft cover 7 and extending in the axial direction Da； a bearing 8 causing the shaft cover 7 to support the turning shaft 9 such that the turning shaft 9 is rotatable about a center axis of the turning shaft 9； and at least one operating wire 78 coupled to the turning shaft 9 at the inside of the wall of the shaft cover 7. The shaft cover 7 includes a guide 74 guiding the operating wire 78. The guide 74 is formed to be symmetrical about a symmetry plane P1 passing through a center axis of the shaft cover 7 and parallel to the axial direction Da. Each of portions of the guide 74 which portions are located at both respective sides of the symmetry plane P1 includes: an outer peripheral portion 743 formed on an outer surface of the wall 70 and extending in the axial direction Da； an inner peripheral portion 744 formed along an inner surface of the wall 70 and extending in a circumferential direction； and a connecting portion 745 connecting the outer peripheral portion 743 and the inner peripheral portion 744.
