To provide an inexpensive snow melting device by mixing hot water and lukewarm underground water heat-exchanged by a heat pump, heat-exchanging inside of a heat-collection well by pressure-injection to the heat-collection well, collecting considerable quantity of soil heat.

In the snow melting device of the soil heat collection well of a heat medium circulation type provided under ground, underground water from adjacent well and the underground water which is hot as a result of heat exchange by passing the underground water through a hot water bath of hot water heat-exchanged by the heat pump. The hot underground water is press-inserted from a hot water press-inserted pipe connected in a fixed manner to a well cover of a soil heat collection well to the heat collection well and conduct heat exchange with circulation heat medium fluid and press-inserted in a nearby stratum to flow the ground water. Thus, underground heat temperature rises and much soil heat collection quantity can be obtained. In addition, the injected hot press-inserted underground water can be returned to the adjacent well by conducting heat exchange with an under ground aquifer.