PURPOSE: To provide a method and a device which can separate a product connected to a work material through a micro-joint with a simple operation.

CONSTITUTION: (1) a process to input data on the work material, data on the shape dimension of the micro-joint to an NC input device 101 connected to a separation device, (2) a process to retrieve an amount of operation of the separation device from a data base 113 connected to the separation device based on the inputted data and (3) a process to set an operating condition of a separator of the separation device based on a retrieved amount of operation are contained in this device. This device is furnished also with the NC input device 101 to input the data on the work material and the data on the shape of the micro-joint, a controller 123 to automatically control the separator and the data base 113 by which the amount of operation of the separator of the separation device can be retrieved based on the inputted data.