To provide a manufacturing device of a printing plate which can make distinct the boundary between a melted and solidified part and a non- melted part.

A thermal head 65 having a plurality of spot-like heating elements 65a is heated selectively on the occasion when it is brought into pressure contact with the surface of a printing material 12A and moved thereon, and thereby a printing face composed of a melted and solidified part being non-permeable to ink and a non-melted part being permeable to the ink is formed. The hardness of the printing material 12A used herein is 20-60 degrees at a temperature of 25°C and the contact pressure of the thermal head 65 and the printing material is set to be 0.1-0.5N/mm for a unit length.