Abstract: A replacement cell determining part is configured so as not to handle, as a cell that should be replaced, the case where the sole difference is the cell identification name and other data are matched, in addition to the case where all of the cell identification name, the cell type name, the pin name of the cell, and the signal name assigned to the pin are matched. A rerouting signal determining part is configured so as not to handle, as a signal that should be rerouted, the case where the sole difference is the signal name and other data are matched, in addition to the case where all of the signal name, the pin name to which the signal is applied, the cell identification name of a cell possessed by the pin, and the cell type name of the cell are matched.