The utility model provides a workpiece processing device, which can not shorten the processing time under the situation that the assembly and the disassembly of a workpiece is time consuming. The workpiece processing device comprises a grinding tool, a workpiece carrying and placing part and a plurality of fixed plate configuration parts, wherein the workpiece carrying and placing part can carry and place a fixed plate for fixing the workpiece as a processing object in assembly and disassembly manners and is provided with an arm capable of moving on the horizontal direction and the vertical direction to be convenient for processing the workpiece in a processing position adjacent to the processing tool in such a manner that the processing tool butts against the workpiece; the fixed plate configuration parts from at least two opposite sides in four peripheral sides for supporting the fixed plate, and any side on the periphery and a central part are opened; when being carried and placed to the workpiece carrying and placing part, the fixed plate can be lifted by the workpiece carrying and placing part from the lower part to be carried and placed; and when being disassembled from the workpiece carrying and placing part, the fixed plate can be configured through falling the workpiece carrying and placing part from the upper part; and the fixed plate configuration parts are alternated between the assembly and disassembly position and the replacement position where the fixed plate is replaced.