To simply reinforce the attachment of a mouse bed by arranging an attaching pole on a desk front leg and attaching a mouse bed to a rockable moving arm on the tip end of a fixed arm protruded in the horizontal direction from the attaching pole.

The attaching mechanism 1 to support a mouse bed 11 is equipped with an attaching pole 18 comprising a square pipe member place by fitting inside the upper end of a front leg 2 comprising a square pipe member of a desk. Further, the mechanism 1 comprises a fixed arm 15 protruded in the horizontal direction at the attaching pole 18 and a movable arm 13 comprising a flat plate member rockably equipped on the tip ene of the fixed arm, an a mouse bed 11 is attached on the tip end of the movable arm 13. Consequently, the attaching pole 18 is selectably fitted into either right or let front leg 2 and a top plate 5 is mounted thereon to enable the under face of the top plate 5 to press and fix the fixed arm 15 and the attaching pole 18. The mouse bed 11 can be easily and firmly attached to the desk via the attaching mechanism fixed in such a manner.