PURPOSE: To manufacture a plate cylinder capable of performing finer multi- gradatin expression by changing the depth and area of a plate corresponding to the light and shade of image data at the time of manufacture of a gravure plate using semiconductor laser.

CONSTITUTION: When cavities 15 are formed on a plate corresponding to the light and shade of image data 41 by semiconductor laser 10, power output is changed by changing the current value and irradiation time value of the semiconductor laser 10 corresponding to light and shade to obtain a plate 2 changed in depth and area.