Abstract: A wheel device and a chair equipped with the same which do not require replacement of a conventional retractable wheel, but instead enable the wheel to be placed in the operating state at all times, as required. The wheel device comprises a wheel and a holder member for holding the wheel. An urging member is arranged between the wheel and the holder member to constantly urge the wheel to be projected in an operable position. A retraction permitting member is adapted to permit the wheel to be retracted while overcoming the urging force of the urging member when a load is exerted in the direction of gravity on a member on which the wheel is mounted. The retraction permitting member includes a setting mechanism for setting the wheel to be in an un-retractable state. The chair is equipped with the wheel devices mounted to a leg portion thereof.