An eye pattern is generated by: simulating a rising step response to a rising step signal input into the circuit and a falling step response to a falling step signal input into the circuit; analyzing a result of the simulating of the rising step response and the falling step response; generating, on the basis of a result of the analyzing, an upper-part test pattern that defines a shape of an upper part of an eye of an eye pattern and a lower-part test pattern that defines a shape of a lower part of the eye of the eye pattern; and simulating a response to the upper-part test pattern and the lower-part test pattern both input into the circuit. This procedure rapidly generates a precise eye pattern.