To provide a plate sticking device which can position a printing plate simply without applying complex processing to the printing plate.

The plate sticking device 10 is constituted by being provided with a printing plate setting-up part 14 for holding the printing plate 12, and a plate cylinder holding part 17 for holding the plate cylinder 11 at a position below the printing plate setting-up part 14. The printing plate 12 has a positioning hole 22 formed in the unprinted part 21 outside the printing surface area 20 of the printing plate 12. The printing plate setting-up part 14 has a projected member 25 which can be fitted in the positioning hole 22. The printing plate 12 can be held at a regular position of the printing plate setting-up part 14 with the projected member 25 fitted in the positioning hole 22.