The present invention provides a desk with which flexibility of a change in the position of an optional member with respect to a base is increased, and by which the position of an optional member with respect to the base can be changed easily and accurately in accordance with the posture of a top board with respect to the base. A desk includes: a base extending in a predetermined direction; a top board capable of selecting a plurality of postures with respect to the base; an option supporting member supported so as to be movable along the base in accordance with the posture of the top board; and a panel system and a task light supported by the option supporting member.