PURPOSE: To form the fine glass electrode excellent in the response, by constituting the shape of sensing film placed at the tip of glass tube as cone shape in which the diameter of tip is around 5W50μ.

CONSTITUTION: The lead glass tubes 1, 1 are incorporatedly bonded in straight line at left and right of the sodium galss tube 2' forming the pH sensing film. Next, the glass tube 2' is heated at about 200°C by the heater 3 to by molten, the lead glass tubes 1, 1 at the both sides are drawn toward left and right, and the sodium glass tube 2' is split left and right as two pieces of hollow cones having the hole 2a. Next, after filling the internal solution (such as KCl water solution) in the holes 1a and 2a with the vacuum replacement method, the cone tip is heated and molten, the tip of the hole 2a is sealed, to obtain the glass tube 1 providing the cone shape detection film 2 at the tip. Next, the internal electrode 4 is inseted in the hole 1a of the glass tube, the tip is in contact with the sensing film 2, and glass electrode is constituted by attaching the grip b.