A process decision support device includes: a machining performance data storage unit that stores machining performance data indicating machining performance of each of a plurality of machining devices including a machining device that adds material and a machining device that removes material; a process pattern generation unit that refers to the machining performance data and sequences and allocates machining steps performed by a combination of any of the plurality of machining devices to generate a process pattern as a combination of the machining steps with which a product is manufacturable; and an output unit that outputs content of the process pattern generated by the process pattern generation unit.