To provide a malfunction-preventing sate to a caster for simultaneously locking, unlocking three items of rotation, horizontal swing motion, and height adjustment of a wheel.

A wheel 16 is installed on a support 15. A second locking body 11 and a first locking body 8 are upward, downward, movably, rotatably fitted in a barrel part 21 projected from the support 15. Rotating the support 15 rotates a screw shaft 18 with the aid of the internal tooth 24 of an intermediate cover 10 and an adjusting gear 7, changing the height of an upper cover 5. Horizontally moving an operating lever 9 to keep cam parts away from both the locking bodies 8, 11 elevates an oscillating locking body 12 by means of a first spring 13 to lock the rotation of the wheel 16. In addition, engaging the thrust gears 24 of both the locking bodies 8, 11 with a ring corrugation 39 locks the rotation of the support 15. Rotating an intermediate ring 10 adjusts height regardless of locking the wheel 16.