This invention relates to a composite processing machine designed so as to be movable in a longitudinal and lateral direction on the side of a work table so that cutting process, discharge process, electrolytic grinding process and the like may be accomplished by a single machine, comprising means for moving a work table (1) on a machine bed (2) in a direction of x-axis and y-axis, a processing unit (9) having a chuck (14) capable of being detachably engaged with various tools and a discharge electrode at the fore end of a spindle (1) positioned upwardly of the work table (1) and comprising a motor (15) for rotating spindle and a fixing brake (12), means for moving a processing unit (9) in a direction of z-axis, an auto tool changer (18) for holding a cutting tool, a discharge electrode, a measuring probe, a grinding wheel and the like to selectively feed them to the chuck, and a processing power source (22) connected over a discharge electrode (26) or a grinding wheel (51) mounted on the chuck (14) and a work (4) within the liquid tank or a nozzle (50) for coolent to apply a dc current to a processing power source (22).