To provide a side chest which can secure favorable fine view and stable condition in condition that the top board is up and is further excellent in operability at ascent and descent of the top board, not to mention combining favorable housing property and work efficiency.

A side chest for a desk is equipped with a side chest body 10, a top board 20 arranged on the topside, a parallel link mechanism 30 to support the top board 20 freely of ascent and descent to the body 10, a horizontal slide mechanism 40 to support the top board 20 slidably in horizontal backward and forward direction, and a guide means 50 to guide the top board 20 roughly vertically to the body 10. Now, this side chest is so constituted that the dislocation in horizontal backward and forward direction of the top board 20 by the ascent and descent of the parallel link mechanism 30 is absorbed and that the topside 20 goes up and down roughly vertically in the guide direction of a guide means 50.