PURPOSE: To accurately measure the response time viewed from a terminal in the job process on the operation of an information system by adding discrimination information to specified information to be processed and determining response time based on the discrimination information.

CONSTITUTION: A discrimination information addition means 15 adds discrimination information enabling the discrimination from the other information to the specified information of the information that a terminal 12 generates in order of time series. In nodes 141 and 142, when a request time detection means 16 transmits discriminated and added information to a processing means 11, the means 16 monitors the discrimination information and determines the processing time of a communication interface. A response time detection means 17 monitors the response that a processing means 11 transmits in the process of the processing performed for transmitted information and determines the processing time of the communication interface transmitting the response to the terminal 12. A response time calculation means 18 obtains the response time on the side of the processing means 11 along a transmission line by taking the difference of the processing time that the request time detection means 16 and the response time detection means 17 determine in this way.