An incubation type planar patch clamp device for nerve cells forming a nerve cell network comprising: an electrically insulating substrate having at least one micro through-hole interconnecting both surfaces of the electrically insulating substrate, the through-hole allowing for passage of liquid while preventing passage of a cell; and a liquid reservoir and an electrode unit disposed on each of a first surface side and a second surface side of the through-hole, the liquid reservoir and the electrode unit being configured such that when a conductive liquid is contained in the liquid reservoir, the electrode unit is in electrical contact with the conductive liquid; wherein the liquid reservoir on the first surface side is configured to receive a cell; characterized in that: the electrode unit on each of the first and second surface sides includes (a) an electrode vessel having a wall of which at least a part is made of an inorganic porous material, and configured such that when a conductive liquid is contained in the liquid reservoir, at least the part of the wall is in contact with the conductive liquid, (b) an electrode contained in the electrode vessel and made of noble metal (Nm), the electrode having a surface layer of chloride of the noble metal (NmCl), and (c) an electrode solution, filled in the electrode vessel, in which the chloride of the noble metal (NmCl) and an alkali metal chloride are dissolved at saturation concentrations, and in that: an extra cellular matrix-forming substance is attached on the circumference of the opening on the first surface side of a through hole on the electrically insulating substrate, wherein the device has a seal resistance of less than 10 MΩ when a cell is disposed on the opening on the through hole, wherein a phase boundary potential at the liquid interface between the electrode solution and the conductive solution is constant. an electrically insulating substrate having at least one micro through-hole interconnecting both surfaces of the electrically insulating substrate, the through-hole allowing for passage of liquid while preventing passage of a cell; and a liquid reservoir and an electrode unit disposed on each of a first surface side and a second surface side of the through-hole, the liquid reservoir and the electrode unit being configured such that when a conductive liquid is contained in the liquid reservoir, the electrode unit is in electrical contact with the conductive liquid; wherein the liquid reservoir on the first surface side is configured to receive a cell; characterized in that: the electrode unit on each of the first and second surface sides includes (a) an electrode vessel having a wall of which at least a part is made of an inorganic porous material, and configured such that when a conductive liquid is contained in the liquid reservoir, at least the part of the wall is in contact with the conductive liquid, (b) an electrode contained in the electrode vessel and made of noble metal (Nm), the electrode having a surface layer of chloride of the noble metal (NmCl), and (c) an electrode solution, filled in the electrode vessel, in which the chloride of the noble metal (NmCl) and an alkali metal chloride are dissolved at saturation concentrations, and in that: an extra cellular matrix-forming substance is attached on the circumference of the opening on the first surface side of a through hole on the electrically insulating substrate, wherein the device has a seal resistance of less than 10 MΩ when a cell is disposed on the opening on the through hole, wherein a phase boundary potential at the liquid interface between the electrode solution and the conductive solution is constant. (a) an electrode vessel having a wall of which at least a part is made of an inorganic porous material, and configured such that when a conductive liquid is contained in the liquid reservoir, at least the part of the wall is in contact with the conductive liquid, (b) an electrode contained in the electrode vessel and made of noble metal (Nm), the electrode having a surface layer of chloride of the noble metal (NmCl), and (c) an electrode solution, filled in the electrode vessel, in which the chloride of the noble metal (NmCl) and an alkali metal chloride are dissolved at saturation concentrations, an extra cellular matrix-forming substance is attached on the circumference of the opening on the first surface side of a through hole on the electrically insulating substrate, wherein the device has a seal resistance of less than 10 MΩ when a cell is disposed on the opening on the through hole, wherein a phase boundary potential at the liquid interface between the electrode solution and the conductive solution is constant.