1. A computer readable recording medium as a communication performance analyzing program that causes a computer to analyze a data tendency of communication performance of a plurality of execution periods of a computer system formed by connecting a plurality of computers by a network, the program comprising: a communication time acquisition step that acquires communication time data among the computers of the computer system; and a statistical analysis step that analyzes the tendency of communication performance data of each execution period of the computer system, using the communication time among the computers, by statistically analyzing the communication time data acquired by the communication time acquisition step.