A process decision support device (100; 101; 102) for supporting decision of a manufacturing process for manufacturing a product, the process decision support device (100; 101; 102) comprising: a machining performance data storage unit to store machining performance data indicating machining performance of each of a plurality of machining devices including a machining device that deposits melted material to shape a three-dimensional object and a machining device that removes material; a process pattern generation unit to select, from among the plurality of machining devices, a machining device applicable to manufacture of the product with reference to the machining performance data, and sequence and allocate machining steps performed by the machining device selected to generate a process pattern as a combination of the machining steps with which the product is manufacturable, wherein the machining devices that are selected by the process pattern generation unit comprise both a machining device that deposits melted material and a machining device that removes material to manufacture the product; a time calculation unit to calculate a time required to complete manufacturing the product according to the process pattern generated by the process pattern generation unit; a cost calculation unit to calculate a cost required to complete manufacturing the product according to the process pattern generated by the process pattern generation unit; and an output unit to output content of the process pattern generated by the process pattern generation unit, a result of calculation by the time calculation unit, and a result of calculation by the cost calculation unit, wherein the output unit outputs a total time and a total cost for the process pattern and a result of time calculation and a result of cost calculation for each of the machining steps in the process pattern, characterized in that based on a shape of the product, the process pattern generation unit divides the product into a plurality of sections for division into machining steps performed by the plurality of machining devices, and allocates machining steps to the sections to generate the process pattern. a machining performance data storage unit to store machining performance data indicating machining performance of each of a plurality of machining devices including a machining device that deposits melted material to shape a three-dimensional object and a machining device that removes material; a process pattern generation unit to select, from among the plurality of machining devices, a machining device applicable to manufacture of the product with reference to the machining performance data, and sequence and allocate machining steps performed by the machining device selected to generate a process pattern as a combination of the machining steps with which the product is manufacturable, wherein the machining devices that are selected by the process pattern generation unit comprise both a machining device that deposits melted material and a machining device that removes material to manufacture the product; a time calculation unit to calculate a time required to complete manufacturing the product according to the process pattern generated by the process pattern generation unit; a cost calculation unit to calculate a cost required to complete manufacturing the product according to the process pattern generated by the process pattern generation unit; and an output unit to output content of the process pattern generated by the process pattern generation unit, a result of calculation by the time calculation unit, and a result of calculation by the cost calculation unit, wherein the output unit outputs a total time and a total cost for the process pattern and a result of time calculation and a result of cost calculation for each of the machining steps in the process pattern, characterized in that based on a shape of the product, the process pattern generation unit divides the product into a plurality of sections for division into machining steps performed by the plurality of machining devices, and allocates machining steps to the sections to generate the process pattern.