To provide an economical construction method for a geothermal heat exchanger being eco-friendly by preventing underground water and ground from being polluted and to provide a hollow pipe body used in this construction method.

This construction method for the geothermal heat exchanger storing a heat exchange medium and buried into the ground to exchange heat between soil heat and the heat exchange medium includes a penetration process for penetrating a casing body part 5 having a function for penetrating into the ground and a cylindrical casing 3 provided with a lid body 8 attached to a distal end of the casing body part 5 openably and closably into the ground by the predetermined depth and a casing pullout process for pulling at least the casing body part 5 out of the ground while the hollow pipe body 1 is arranged inside the casing 3.