The invention provides a linear cutting machine for sponge. The linear cutting machine comprises a machine frame, a left working platform and a right working platform, wherein the left working platform and the right working platform are arranged at the upper end of the machine frame; a gap is reserved between the left working platform and the right working platform, a metal gasket is arranged outside the right side of the left working platform in a sleeving mode, and a metal gasket is also arranged outside the left side of the right working platform in a sleeving mode; two grooves are formed in the longitudinal surface of the right working platform, the interiors of the grooves are each of a tooth-shaped structure, and pinions are further arranged in the grooves and mesh with the grooves; a limiting plate is further arranged at the upper end of the right working platform, and a rocking handle is further fixed at the front end of the limiting plate and comprises a rotating disc and a rotating rod, and the tail end of the rotating rod extends to the inner side of the limiting plate and is fixed on the inner side of the limiting plate through a flange plate; a big gear is further arranged outside the rotating rod in a sleeving mode, meshes with the pinions and is also located on the inner side of the limiting plate; and a meter ruler is further attached to the surface of the right working platform.