A combination electrode for ion concentration measurement is provided including a glass electrode and a reference electrode whose internal electrode is made of silver-silver chloride, wherein a sealing means is provided configured to seal an upper surface of a reference electrode chamber formed in an outer tube which houses an internal electrode and an internal solution of the reference electrode, and around a glass support tube penetrating the outer tube along a substantially center axis thereof an annular silver member which the glass support tube penetrates along a center axis thereof, annular sealing elastic members for liquid-tightly sealing a space between the silver member and the glass support tube, and a space between the silver member and the outer tube, respectively, and the reference electrode internal electrode is connected to a terminal for a reference electrode through the silver member.