The present invention relates to a guide unit for measurement acting as a guide for measuring the micro-weight of fine grains having minute weight and volume, such as powders, granules, seeds and pills, and to a micro-weight measuring system for accurately measuring the fine grains by a preset micro-weight by using the guide unit for measurement. The present invention has an effect of being capable of measuring the micro-weight as a unit to thereby package fine grains such as powders, granules, seeds and pills by micro-weight unit. In addition, the present invention has an effect of being capable of accurately measuring the fine grains by the preset micro-weight in such a manner that in the procedure of discharging a one-unit-micro-weight of the fine grains, some of the fine grains are discharged at a smaller amount than the initially-discharged amount and are finally discharged by dropping.