A double-pipe geothermal water circulating apparatus including an outer pipe having a geothermal water supplying strainer for infiltrating geothermal water from an aquifer and a geothermal water returning strainer for returning used geothermal water to the aquifer, a thermal insulation inner pipe composed of a thermal insulator that forms a flow channel with the outer pipe, a pump for pumping the geothermal water from the thermal insulation inner pipe, a heat source supplying force feed pipe for force-feeding pumped geothermal water to an heat exchanger and a heat source reusing pipe connected to the flow channel for returning the used geothermal water to the aquifer. Also, the double-pipe geothermal water circulating apparatus is provided therein with the flow channel from the geothermal water returning strainer to the geothermal water supplying strainer that is not separated, whereby geothermal water can flow therethrough.