A communication performance analyzing program, a communication performance analyzing apparatus and a communication performance analyzing method make it possible to highly reliably grasp the communication performance of a computer system by automatically analyzing the communication performance. The 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 comprises a communication time acquisition step S2 that acquires communication time data among the computers of the computer system and a statistical analysis step S3 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.