The present invention discloses a method for displaying gene expression patterns of multiple genes that change according to the experiment cases, where a first axis represents the genes and a second axis represents the experiment cases. The method comprises two steps. The first step consists of designating a segment along the second axis in the expression pattern data of the multiple genes. The second step comprises clustering the expression pattern data within the designated segment along the second axis based on a predetermined reference value, repeating clustering within the same cluster in a forward or reverse direction along the second axis while changing the reference value, and displaying the results according to a predetermined display format.