A plurality of semiconductor integrated circuits have the same configuration as that of an LSI which is subjected to debugging. Different internal signals are respectively collected from the semiconductor integrated circuits under the same operation conditions. The operation of the LSI is analyzed based on the collected internal signals. By doing this, it is not necessary to add output terminals to the LSI or switch the internal signals output from output terminals at periodic time intervals. This facilitates the debugging of the entire LSI in a low-cost and simple configuration.