PURPOSE: To perform the system analysis of an industrial computer system with a light load, by providing a gathering and analyzing circuit which accepts gathering start and stop requests of events of various programs and gathers and analyzes data related to events for these requests.

CONSTITUTION: When receiving a start request signal (a) from a start and stop request circuit 20, a data selective gathering circuit 30 issues a connection request (d) to an electronic computer 10. The circuit 30 takes in data related to events from a storage 1 of a circuit 40 and writes it in a storage 2 of a circuit 50. If a stop condition is satisfied, a disconnection request (e) is issued, and a start request (c) is outputted to a data analyzing circuit 60. When the circuit 30 receives a stop request signal (b), the disconnection request (e) of the data selective gathering circuit 30 is outputted to the computer 10, and the start request (c) is outputted to the analyzing circuit 60. When receiving this start request, the analyzing circuit 60 reads in data from the storage 2 and arranges data on a basis of the analysis condition of a storage 3 of a data analysis condition storage circuit 70 and writes data in a storge 4 of an analyzed data storage circuit 80.