NOVELTY - Heat exchanger (10) used for geothermal heat pump system comprises heat exchanger tube positioned so that continuous loops (12a) may be located in a line; and holder (14), which connects a burying display tape (T), which is positioned above the heat exchanger tube and has flexibility, where the holder has a tape holding part (16), which carries out state change from a holding state where burying display tape is held by operation to releasing state where burying display tape is movable along an extension direction, and a tube holding part (24), which holds the heat exchanger tube.    USE - Heat exchanger used for geothermal heat pump system.    ADVANTAGE - The heat exchanger tube is aligned flexibly, achieving efficient heat exchange. It can be installed easily. The holder cannot interfere with the groove easily and can align the loop appropriately. Since the loop of the heat exchanger tube is appropriately aligned with the holder, the heat exchanger can achieve heat exchange as designed. The adjacent loops are spaced apart by the holders with which the heat exchanger adjoins each other in the burying display tape. Thus, heat-exchange between the loops is prevented and the contact area of soil and heat exchanger tube is increased, achieving efficient heat exchange. Since the burying display tape buried above the heat exchanger tube is used as a reference of space adjustment of the holders, a number of parts can be minimized.    DETAILED DESCRIPTION - Heat exchanger (10) used for geothermal heat pump system and buried in the ground comprises heat exchanger tube (12) positioned so that continuous loops (12a) may be located in a line; and holder (14), which connects a burying display tape (T), which is positioned above the heat exchanger tube and has flexibility, where the holder has a tape holding part (16), which carries out state change from a holding state where burying display tape is held by operation to releasing state where burying display tape is movable along an extension direction, and a tube holding part (24), which holds the heat exchanger tube so that attachment or detachment is possible. The holder is spaced apart in the extension direction of the burying display tape and arranged on the burying display tape via the tape holding part. The loop of the heat exchanger tube in space adjustment with the holder is held by the tube holding part to be aligned. An INDEPENDENT CLAIM is included for installation method of heat exchanger.    DESCRIPTION OF DRAWING(S) - The drawing is a side view of heat exchanger.    Heat exchanger (10)    Heat exchanger tube (12)    Loops (12a)    Holder (14)    Tape holding part (16)    Tube holding part (24)    Burying display tape (T)