A fixing mechanism for storage device includes a frame, and a detent component. One sidewall of the frame has a latch member. The detent component is movably disposed on the sidewall of the frame, and has a pressing component and an operating component. The operating component is disposed with at least one stop block. When the operating component is moved relative to the frame to a press position, the pressing component pushes the latch member to engage with the storage device, the stop block is embedded in the frame, and the detent component is held in the press position. Accordingly, the storage device may be fixed to the frame rapidly without using any screw, the operating procedure is dramatically simplified, and the space occupied by the fixing mechanism and the manufacturing cost are reduced.