A plate inserting apparatus includes a plate cylinder, press roller, and braking unit. A plate is to be mounted on the outer surface of the plate cylinder. The press roller is rotatably supported to oppose the outer surface of the plate cylinder. When the leading edge bent portion of the plate to be supplied to the plate cylinder abuts against the press roller and the distal end of the leading edge bent portion abuts against the outer surface of the plate cylinder, the press roller inserts the leading edge bent portion of the plate into a groove portion formed in the plate cylinder upon rotation (with a pressing force) of the plate cylinder. The braking unit keeps braking the plate at least since the leading edge bent portion of the plate abuts against the outer surface of the press roller and until the leading edge bent portion is completely inserted in the groove portion of the plate cylinder.