PURPOSE: To make compact and light-weight a countermeasure device for power failure and prevent the consumption of energy by a method wherein a capacity is provided in parallel with each other on the power source side of a microcomputer containing memory holding elements according to voltage or the power source side of memory elements.

CONSTITUTION: The output of a load cell 10 is inputted to a microcomputer 16 via a preamplifier 12 and an AD converter 14 and processed through computation. A large capacity electrolytic capacitor 42 is connected in parallel to a series switch 38 of the power source 40 of the microcomputer 16. Otherwise, a capacitor 44 is connected in parallel only to an RAM30 in order to reduce the cost of a capacitor, so that the elimination of memory in the RAM due to power failure for a short period is prevented. By so doing, the countermeasure device for the power failure can be made compact and light-weight, while power consumption can be prevented.