PURPOSE: To decrease the trace data information to be sampled adapting to the contents of trace data at the time of sampling.

CONSTITUTION: A trace processing means 2 reads input trace data 12 to provide trace input information 11 from a trace object program with a trace data providing means 1 and refers to trace processing change information in trace processing information 15 from a trace processing information means 4. According to the trace processing information 15 to be changed only when necessary, prescribed trace processing is executed and the result is written out as output trace data 13. The output trace data 13 are received by a trace data receiving means 3 as trace output information 14. The trace processing information means 4 holds the trace processing information 15 containing the trace processing change information for setting possibility judgement conditions to change the trace processing corresponding to the contents of the input trace data. Thus, an adaptive trace processing system can be provided to efficiently analyze the position of a fault and to economize resources for preserving data.