To provide a bracket attachment which works for shelves with different depths by easy handling and can be used as a bracket attachment for either right or left side.

The bracket attachment is made up of a main part 1 of an attachment and an auxiliary attachment 2 joined to the main part 1 of the attachment as it can be attached and removed. The main part 1 of the attachment has an L-shaped front. One of the securing parts 11 of the attachment is secured to a surface 3 to install such as a wall, and a shelf 4 is put on the other securing part 12. The auxiliary attachment 2 is made up of a securing part 21 for the auxiliary attachment 2 and a piece 22 to put an overhanging shelf which is joined to the securing part 21 for the auxiliary attachment serially. The securing part 21 is placed over and fixed to the other securing part 12 of the main part 1 of the attachment in a manner that it can be removed and attached while the length of the projecting piece 22 to put the overhanging shelf is set so that the upper surface of the other securing part 12 of the main part 1 found on the attachment and the upper surface of the piece 22 of the auxiliary attachment 2 meet in a plane.