Abstract: The invention is featured in that the natural language process can be made in a way that a chained functions structure expressing relationships among concepts of elements of the natural language constructing the character strings is generated, a rule table which stores in advance rules of association relationship between the chained functions structure and form of a command language which the processor system can execute is looked up, the generated chained functions structure is converted to a form which the process can be executed, and the command language are obtained as results of the analysis by incorporating the information as to the operating statuses of the processor system into the converted form. The invention enables the computer to operate in a desired mode with input of usual natural language without use of any of the formal languages usually given to the computer (special languages and command defined for the computer).