To provide an electrolyte composition having good durability, ion conductivity and electric charge carrying performance, and to provide an electrochemical cell, a photoelectrochemical cell, and a nonaqueous secondary battery having good photoelectric conversion efficiency and durability by using the same.

The electrolyte composition comprises a polysiloxane having a structure expressed by general formula (I) shown below as a repeating unit and an ionic compound showing mesomorphism. The electrolyte composition is used for the electrochemical cell, the photoelectrochemical cell, and the nonaqueous secondary battery. In the following general formula (I), R1 and R2 show, independently, an alkyl group or an alkyleneoxy group.