To provide a heat pump system capable of reducing a labor and time and a cost for maintenance of a heat pump.SOLUTION: A heat pump system comprises: a supply line 2 for guiding water to be used at a water use facility 3 as guided water W1 to the water use facility 3； and a heat transfer part 8 for performing heat exchange between a heat source W2 being a fluid and the guided water W1. The heat transfer part 8 has: a heat pump part 12 having a heat medium circulation line 9 in which a heat medium M1 is circulated between a compressor 10 and an expansion valve 11； a supply side heat exchange part 13 for performing heat exchange between the heat medium M1 and the guided water W1； and a heat source side heat exchange part 14 for performing heat exchange between the heat medium M1 and the heat source W2. At least one of the supply side heat exchange part 13 and the heat source side heat exchange part 14 has: intermediate heat medium circulation lines 13C, 14C in which an intermediate heat media M2, M3 is circulated； heat exchangers 13A, 14A for performing heat exchange between the intermediate heat media M2, M3 and heat medium M1； and heat exchangers 13B, 14B for performing heat exchange between the intermediate heat media M2, M3 and guided water W1 or heat source W2.SELECTED DRAWING: Figure 1【課題】ヒートポンプのメンテナンスにかかる手間とコストを軽減し得るヒートポンプシステムを提供する。【解決手段】水使用設備３にて使用する水を導入水Ｗ１として前記水使用設備３に導く供給ライン２と、流体である熱源Ｗ２と導入水Ｗ１との間で熱交換を行う熱移送部８とを備え、前記熱移送部８は、圧縮機１０と膨張弁１１との間を熱媒Ｍ１が循環する熱媒循環ライン９を備えたヒートポンプ部１２と、熱媒Ｍ１と導入水Ｗ１との間で熱交換を行う供給側熱交換部１３と、熱媒Ｍ１と熱源Ｗ２との間で熱交換を行う熱源側熱交換部１４とを備え、前記供給側熱交換部１３または前記熱源側熱交換部１４の少なくとも一方は、中間熱媒Ｍ２，Ｍ３が循環する中間熱媒循環ライン１３Ｃ，１４Ｃと、中間熱媒Ｍ２，Ｍ３と熱媒Ｍ１との間で熱交換を行う熱交換器１３Ａ，１４Ａと、中間熱媒Ｍ２，Ｍ３と導入水Ｗ１または熱源Ｗ２との間で熱交換を行う熱交換器１３Ｂ，１４Ｂを備える。【選択図】図１
