To provide a headrest rotating device of a treatment table, which is easy to operate, has a simple structure, is manufactured at a low cost and can make a subtle movement in treating a patient by a simple operation.

The device is provided with a rotary shaft 7 provided on a pillow tilting support plate 6, a pillow base plate 8 rotatably supported by the rotary shaft 7, a cylinder body 10 which is rotatably held to the rotary shaft 7 (a bracket 7b) by a shaft 10a and provided with a female screw thread 10b inside and a male screw thread shaft 11 which is threaded through the female screw thread 10b inside the cylinder body 10. At the same time the pillow base plate 8 is rotated back and forth by the rotation of the male screw thread shaft 11.