PURPOSE: To grasp not only failures generated in the market but also failures generated in a plant by providing a failure code memory with a plant memory area and a market memory area.

CONSTITUTION: A failure code memory 15 is provided with a plant memory area formed of n=00-7F totaling to 128, and a market memory area formed of n=80-FF totaling to 128. Each memory address 16 is formed of 8 bits. The memory address 16 of n=00 in the plant memory area is stored with a plant delivery flag set at the time of delivering products from a plant. The memory addresses 16 of n=01-7F form a plant failure code memory area stored with the information of failures generated during the production of products. The memory address 16 of N=80 in the market memory area is stored with the added information of failure generation in the market. The memory addresses 16 of n=81-FF form a market failure code memory area stored with failures generated in the case of the plant delivery flag being set, that is, failures generated in the market after delivery.