To provide a plate material processing system capable of efficiently feeding a stock plate in an automated warehouse to a plate working machine when plates of many kinds in small quantities are processed.

A plate processing machine 2 processes a stock plate W delivered from an automated warehouse 1. Individual shelves 5 for loading pallets by kind with stock plates W of a single kind being loaded on a pallet 10 are provided on three-dimensional shelves 3A, 3B of the automated warehouse 1. A plurality of pallet-by-kind arrangement places 12A, 12B, 12C, and a pallet arrangement place 15 for mixed loading are provided on the three-dimensional shelf 3A. The pallet-by-kind is transferred by a stacker crane 6 onto the pallet-by-kind arrangement places 12A, 12B, 12C from the individual shelves 5. The stock plates W on the pallet-by-kind arranged on the pallet-by-kind arrangement places 12A, 12B, 12C are transferred to the pallet 10 for mixed loading arranged on the pallet arrangement place 15 for mixed loading. A pallet for mixed loading with a plurality of kinds of stock plates W being mix-loaded is generated on the pallet 10.