PURPOSE: To enable a stable power feed, without using a battery, by parallel connecting a solar cell module composed of thin film solar cell elements to a solid-state thin film secondary cell.

CONSTITUTION: To a solar cell module, a solid-state thin film secondary cell composed bf many Li thin film secondary cell unit cells 7 formed on an insulation substrate 6 is faced and sealed with a resin 4. This module and secondary cell are parallel connected by a wiring 8 between positive and negative terminals 51 and 52 through inserted backward diodes or controls as required. The power generated by the solar cell at irradiation of light is stored in the secondary cell and the power discharged from the secondary cell at the dark time is supplied. Accordingly, a stable power feeding can be made, without using a battery.