1. A verification program of a program for causing a computer to verify a concurrent program or a parallel program composed so as to include a plurality of functions after an alteration made to the program to be verified, the verification program being adapted to cause a computer to execute: a detection step that detects the function that has been altered and the function that uses a shared variable influenced by the alteration along with the first part that includes the altered part of the altered function and the influenced part of the function using the shared variable influenced by the alteration, and the control structure part relating to the control of program processing and the second part other than the control structure part and the first part out of the program to be verified before and after the alteration made to the program to be verified; a model generation step that generates a model of the program to be verified before the alteration and a model of the program to be verified after the alteration on the basis of the control structure part, the first part and the second part detected in the detection step; and a verification step that verifies the program to be verified after the alteration by comparing the model of the program to be verified before the alteration and the model of the program to be verified after the alteration, the models being generated in the model generation step.