The invention aims to provide a health care instrument adapted to measure oxidation-reduction potential in human being, animal, fish and shellfish, plant, vegetable as well as water, air or earth surrounding those organisms and thereby to determine a level of active oxygen in such subject so that the measured data may be used for health care. The object set forth above is achieved by a health care instrument containing an oxidation-reduction potential measuring function comprising a main body, a power source consisting of a battery with or without a battery charger and an oxidation-reduction potential measuring unit both contained in the main body, a measuring probe attached to one end of the main body, a sensor included in the measure probe so as to be connected to the oxidation-reduction potential measuring unit, and a display unit provided on a part of the main body to display the measured oxidation-reduction potential value. The health care instrument according to the invention allows the oxidation-reduction potential in the subject to be easily determined in order to know a condition of the subject's health or growth. The health care instrument allows an internal abnormal condition to be detected and thereby allows the subject to be prevented from being affected by disease. Thus, the health care instrument according to the invention effectively contributes to health care.
