An operation analyzing apparatus (100) for semiconductor integrated circuits according to this exemplary embodiment includes a simulation analyzing unit (140), and the simulation analyzing unit (140) includes: a semiconductor characteristics extracting unit (110) that extracts the inductances L, resistances R, and capacitances C of a board, a package, and a semiconductor integrated circuit, from the semiconductor integrated circuit mounted on the board via the package; an individual network generating unit (111) that generates individual networks of the extracted inductance L, resistance R, and capacitance C with respect to each of said semiconductor substrate, said package, and said semiconductor integrated circuit; an integrated network generating unit (112) that generates an integrated network by integrating all of the generated individual networks; and an operation simulation running unit (113) that performs an operation simulation of the semiconductor integrated circuit by inserting a test noise pattern to an arbitrary position in the generated integrated network.