A fixing member, a device for mounting a circuit board, and a display apparatus so as to conveniently and firmly fix a PCB on the back plate of the back-light module are disclosed. The fixing member includes a supporting plate, a first clamping part fixedly arranged on an upper surface of the supporting plate, and a second clamping part facing the first clamping part. The first clamping part and the supporting plate form a first U-shape clamping groove. The second clamping part and the supporting plate form a second U-shape clamping groove. An opening of the first U-shape clamping groove faces an opening of the second U-shape clamping groove. The fixing member is used for fixing the circuit board on the back plate.