An anti-kickback device includes a riving knife mounted rearwardly of a saw blade of a table saw machine and having a retaining hole. An elongate mount has a cavity and an insert groove to receive the plate body such that the retaining hole is located in the cavity. A fastening unit includes a post which is received in the cavity, which straddles a top surface of the knife, and which has a radial bore registered with the retaining hole, a detent body disposed in the radial bore and movable to extend into or to be clear of the retaining hole to thereby permit the mount to be secured to or detached from the knife, a tubular actuator which has an inner cam surface configured to move the detent body, and an operating member manually operable to move the actuator.