To design the circuit of ICE target (22) of a CPU (21) at the time of designing the CPU (21) to simplify the simulating operation of following systems and to perform online verification of a circuit system to easily solve a problem immediately at the time of finding the problem during manufacturing of the circuit system.

A matching device for emulator and processor is provided with a circuit main body, one processor installed in the circuit main body, and an emulator which is installed in the circuit main body and is electrically connected to the processor to simulate the operation of the processor in accordance with commands and displays the simulation effect of the processor in order to verify the accuracy of the circuit system electrically connected to the processor and makes the processor directly control the circuit system in the case of no errors in the verification.