Abstract: A holding device for mounting and holding a plurality of caulking canisters and a caulking gun thereon. The holding device includes a back board for vertical mounting having a plurality of holes for mounting the back board to a vertical surface, the back board having an upper section, a center section and a lower section. The holding device further includes a shelf having a plurality of recessed seats for receiving the bottom ends of the caulking canisters, the shelf being connected to the center section of the back board. The holding device also includes a plurality of support rings in alignment with the plurality of recessed seats for receiving the upper end of the caulking canisters, the plurality of support rings being connected to the upper section of the back board. Two mounting brackets are provided for receiving and mounting a caulking gun thereon, the two mounting brackets being connected to the lower section of the back board.