The invention provides a machine tool auxiliary roller device which comprises an adjusting nut, a screw, a locking nut, a detaching frame, an idler wheel, a first locking block, a support sliding block, a locking sliding block, a second locking block and a sliding rail, wherein the adjusting nut is arranged on the upper side of the annular side face of the screw; the screw is arranged in the middle of the interior of the detaching frame; the locking nut is arranged on the lower side of the annular side face of the screw; and the detaching frame is arranged on the upper end face of a support plate. The machine tool auxiliary roller device solves the problem that the central frame of the original machine tool roller device is inconvenient to detach and use; the idler wheel is arranged on theupper end face of a support block; the first locking block is arranged on the left side of the upper end face of the support plate; the support sliding block is arranged on the lower end face of thesupport block; the locking sliding block is arranged on the lower end face of the first locking block; the second locking block is arranged on the right side of the upper end face of the support plate; and the sliding rail is arranged in the support plate. The machine tool auxiliary roller device solves the problems that the original machine tool roller device is inconvenient to detach and largerin size, and is reasonable in structure, convenient and fast to detach and convenient to use.