A method of analyzing transmission characteristics of signal wiring in a circuit apparatus including the signal wiring and insulative layer is disclosed. The transmission characteristics are analyzed by dividing the circuit apparatus with a mesh and applying electromagnetic analysis method to each unit of the mesh. The method includes the steps of: extracting signal wiring data from 3 dimensional data of the circuit apparatus; designating a sparse mesh region in which the mesh can be made sparse based on the extracted signal wiring data and the 3 dimensional data; and generating sparse mesh in the sparse mesh region. Since the sparse mesh region is designated based on the sizes of the signal wiring and the insulative layer and on the electric properties of the insulative layer, a region that affects the transmission characteristics of the signal wiring only to a small extent can be designated as the sparse mesh region.