Abstract: A retractable castor mechanism for attachment to an article of furniture or other heavy object including a castor shank that is rotatably received by a socket of a retaining member. A mainspring biases the retaining member and the castor downwardly, and a latch pin is engageable with the retaining member to latch the castor against the force of the spring in an inoperative retracted position. The latch is operated by a releasing lever having a foot portion that rests against the floor, so that a slight push of the article across the floor causes the latch pin to disengage the retaining member, allowing the castor to descend to an operative position.