A tank retaining bracket having a rotating head for selectively receiving and securing a tank to the bracket having a mounting cup preferably of nylon which adapted to abut and hold a cylindrical tank in an inverted position in a positively engaging manner. The mounting cup includes an arcuate retaining surface and can easily replaced during normal maintenance. The mounting cup is attachable to the rotating head of the bracket frame of a positively engaging tank holder usable with cylindrical tanks such as self-contained breathing apparatus primarily for facilitating adjustability of positioning of retaining of the tank with respect to the mounting bracket. The body member is adjustably movable to a multiple of lateral directions such that it is firmly secured in place by a plurality of fasteners and engagement is further enhanced by a ridge on the rotating frame head and a mated engaging block on the mounting cup.