To provide a computer system that makes it possible to easily operate a computer without requiring special practice and training and an operation processing method in the computer system.

A stand-alone computer system which is not connected to a network or a computer system connected to a two-way communication network is provided with a two-dimensional code reading means for optically reading a plurality of operation items showing items needed to operate the computer system, a two-dimensional code of an operation sheet on which the two-dimensional code having information for making the computer system perform operation about the operation items in the vicinity of the operation items and the two-dimensional code displayed on a display in a similar manner, generating image data and giving the generated image data to the computer.