Upon receiving debugging program activation instructions sent from a communication port (1), debugging program activation instruction distribution units (61 and 71) distribute the received debugging program activation instructions to execution units designated by these activation instructions. Debugging program activation units (62 and 72) are provided for each execution unit (A and B) and, based on the activation instructions distributed by the activation instruction distribution units (61 and 71), activate debugging programs (63 and 73) on the execution units designated by these activation instructions.