An object of the present invention is that variations in an applied membrane potential in the planar patch clamp device are suppressed to reduce a noise current, thereby enabling accurate measurement of an ion channel current.Disclosed is a planar patch clamp device including: an electrically insulative substrate provided with one or more fine through holes; a liquid reservoir that holds a conductive liquid provided on both surface sides of the through hole; and energizable electrode sections provided in the liquid reservoir; these electrode sections including: (a) an electrode vessel, at least part of which is made of an inorganic porous material, (b) an electrode in which a chloride NmCl layer is formed on the surface of a noble metal Nm, and (c) an electrode solution containing NmCl and an alkali metal chloride being dissolved therein at a saturated concentration.