To form a marble pattern with a linear and homogeneous pattern little generation of a fading or unevenness which is a defect on the calender method on the surface of a sheet made from a resin.

An apparatus is provided which consists mainly of one extruder provided with a T-die and a calender roller, a resin composition containing both of a pigment beginning coloring at 120 to 130C and a pigment beginning coloring at 140 to 150C is charged into the one extruder, it is extruded through the T-die and rolled with a calender roller, if necessary, a substrate cloth and a film to serve as the surface layer are extruded to a nip of the calender roller.