Cutting apparatus for making cuts on pipes made of plastics, in particular PVC, comprising: - a supporting disk rotatable about a rotation axis and provided with a respective central opening for inserting a pipe to be cut in a work configuration; - at least one cutting tool supported by said supporting disk via first support means and movable at least towards said rotation axis in order to abut and cut a side wall of said pipe; - an adjustment disk coaxial to, and rotatable with, said supporting disk and having with respect to the latter a respective adjustable angular position about said rotation axis, said adjustment disk being provided with a respective central opening for inserting said pipe and at least first moving means for moving said cutting tool at least towards said rotation axis when an angular position of said adjustment disk with respect to said supporting disk is changed; - driving means for moving said supporting disk and said adjustment disk about said rotation axis with respective rotation motions having the same revolving speed and comprising a first driving pulley, rotating said supporting disk by means of a first belt, and a second driving pulley, rotating said adjustment disk by means of a second belt; - adjustment means associated with said driving means and arranged for changing said angular position of said adjustment disk with respect to said supporting disk; characterized in that said adjustment means comprise a couple of adjustment pulleys fixed to a mobile adjustment carriage and engaged by said second belt, said adjustment pulleys being movable with said adjustment carriage along an adjustment direction in order to move a branch of said second belt engaging said adjustment disk so as to change the angular position of said adjustment disk with respect to said supporting disk, said adjustment pulleys being further eccentrically fixed to said adjustment carriage so as to rotate eccentrically and in phase when moved by said second belt for generating an oscillating component in said rotation motion of said adjustment disk so as to move said cutting tool with a linear reciprocating motion when moved by said first movement means of said adjustment disk towards said rotation axis. - a supporting disk rotatable about a rotation axis and provided with a respective central opening for inserting a pipe to be cut in a work configuration; - at least one cutting tool supported by said supporting disk via first support means and movable at least towards said rotation axis in order to abut and cut a side wall of said pipe; - an adjustment disk coaxial to, and rotatable with, said supporting disk and having with respect to the latter a respective adjustable angular position about said rotation axis, said adjustment disk being provided with a respective central opening for inserting said pipe and at least first moving means for moving said cutting tool at least towards said rotation axis when an angular position of said adjustment disk with respect to said supporting disk is changed; - driving means for moving said supporting disk and said adjustment disk about said rotation axis with respective rotation motions having the same revolving speed and comprising a first driving pulley, rotating said supporting disk by means of a first belt, and a second driving pulley, rotating said adjustment disk by means of a second belt; - adjustment means associated with said driving means and arranged for changing said angular position of said adjustment disk with respect to said supporting disk;