Described is a natural leather trimming machine including: an ironing device for stretching and removing creases and wrinkles from the leather, cutting means for cutting the leather along at least one cutting line, a detection unit configured to detect the position of the leather, the shape of at least one relative end edge, and the position of any defects close to at least one relative end edge, a plurality of conveyor belts and a first command and control unit configured to determine the cutting coordinates of the leather.