PROBLEM TO BE SOLVED: To provide a 3D data display system capable of displaying a 3D data image in a viewpoint from various angles by rotatingly displaying the 3D data on a display screen of a user terminal.SOLUTION: A server 10 includes: a storage unit that stores the 3D data related to medical treatment including prophylactic methods, treatment steps and technical materials, associated with identification information included in a marker 31 and 3D data extraction means that searches the storage unit to extract the 3D data and transmits them to a user terminal 20. The user terminal includes: reading means for reading the marker 3D data acquisition means that transmits the identification information read by the reading means and acquires the 3D data from the server display means that displays the 3D data acquired by the 3D acquisition means gradient detection means that detects a gradient of the own user terminal according to the operation of the user and display control means that displays the 3D data displayed on the display means by rotating them corresponding to the gradient of the own user terminal detected by the gradient detection means.
