Abstract: A liquid film type, chloride ion-selective electrode is provided with the present invention, which comprises a sensitive film containing a polymeric material as a support film material, a tetraalkyl ammonium salt with four alkyl group each having 10-24 carbon atoms as a chloride ion-sensitive substance, and a mixture of a linear alcohol having a low dielectric constant with at leastg 10 carbon atoms and an organic compound having a dielectric constant higher than that of said linear alcohol as plasticizer. This electrode has a high selectivity over lipophilic anions and hydrophilic anions, high accuracy ion measurements, and a long life.