PURPOSE: To provide a method for producing the subject paper base material for image-transferring receptor sheet or the like by coating the front side of a paper base material with a thermoplastic polymer in an extruding way and by passing it between nip rolls one surface of which has a lower temperature than the polymer and the other of which has differential surface characteristics to be visually observed, thus obtaining the above base material.

CONSTITUTION: This method comprises: coating one surface of a paper base material with a thermoplastic polymer (e.g. polyolefin) in an extruding way; passing it between a pair of nip rolls; contacting the polymer with one of the rolls having a lower temperature than the polymer for cooling it; and forming a visually observable image on the paper base material by cooling one of the nip rolls because the surface of the other nip roll is provided with differential surface characteristics.