Abstract: The present claimed invention provides a calcium ion concentration measuring device that can measure a concentration of a calcium ion in blood of a domestic animal with high accuracy without being affected by temperature on the spot where the blood is collected. The calcium ion concentration measuring device is a portable one for measuring the concentration of the calcium ion in the blood of the domestic animal, and comprises a responsive membrane that selectively reacts with the calcium ion, an internal liquid stored in a space separated from the outside by the responsive membrane, and an internal electrode arranged to be in contact with the internal liquid, and the isothermal intersection point of the internal liquid is set within a range of the concentration of the calcium ion contained in the blood of the domestic animal.

Abstract: The present claimed invention provides a calcium ion concentration measuring device that can measure a concentration of a calcium ion in blood of a domestic animal with high accuracy without being affected by temperature on the spot where the blood is collected. The calcium ion concentration measuring device is a portable one for measuring the concentration of the calcium ion in the blood of the domestic animal, and comprises a responsive membrane that selectively reacts with the calcium ion, an internal liquid stored in a space separated from the outside by the responsive membrane, and an internal electrode arranged to be in contact with the internal liquid, and the isothermal intersection point of the internal liquid is set within a range of the concentration of the calcium ion contained in the blood of the domestic animal.