To provide a printing plate which enables an expansion amount of a blanket to be determined by visually inspecting an object to be printed.

By rolling contact of the blanket wound on a blanket cylinder coated with ink with the printing plate 1 and the top surface of the object to be printed in sequence, excess ink on the blanket is removed by the convex part of the printing area, and the remaining ink on the blanket is transferred onto the object to be printed for offset printing. The printing plate 1 has a plurality of concave parts 15 of different depths on its non-printing area 14.