PURPOSE: To reduce the capacity of a trace memory and to improve work efficiency concerning the device for collecting trace data used for the evaluation test or analysis of a program.

CONSTITUTION: This device is equipped with a collection part 3 to collect the trace data by simulating a program 2 to be tested, compression part 4 to compress the trace data from the collection part 3 so as to be restored, restorage part 5 to restore the compressed data to a state before the compression and to transfer the data to an external device 8, and memory area monitor part 7 to record the compressed data from the compression part 4 in a trace memory 6 while monitoring the remaining memory capacity of the trace memory 6 when there is a space in the memory, to interrupt the processing of the collection part 3 when there is no space and to restart the processing of the collection part 3 after restoring/transferring all the data in the trace memory 6 by activating the restorage part 5.