To reduce the number of man-hours and the cost for designing and manufacturing furniture leg caps.

A cap body 10 is formed as a bottomed cylinder, and four projections 11 with inclined faces 11A along the circumferential direction are continuously formed on the inner wall of the cylinder. A rotary hollow lid 20 comprises a ring part 21 with a groove 21A and four plate pieces 22 corresponding to the four projections 11 of the cap body 10 to extend from the lower end of the ring part 21. The upper part of the cap body 10 is rotatably fitted into the groove 21A of the rotary hollow lid 20. By rotating the rotary hollow lid 20, the four plate pieces 22 run on the four projections 11 along the inclined faces 11A to the height corresponding to the angle of rotation.