1. A device for diagnosing thermal images, comprising: an acquiring part for acquiring thermal imaging data; a body information selecting part for selecting body information from the body information stored in a storage medium, the storage medium being used for storing the body information and the constituted data related to the body information; the body information being composed of attribute information of multiple attributes, and the body information being finally selected via display and multiple selections for the attribute information of multiple attributes of the body information; a display controlling part for controlling to display a reference image acquired according to designated constituted data and an infrared thermal image generated by the acquired thermal imaging data together according to a position parameter of the reference image located in the infrared thermal image, the reference image reflecting morphological characters of a photographed body; a thermal image analyzing part for analyzing the thermal imaging data acquired by the acquiring part to acquire an analysis result, according to a specified analysis mode, based on a specified analysis area; a diagnosing part for diagnosing according to a specified diagnosis rule to acquire a diagnosis result according to the analysis result acquired by the thermal image analyzing part; wherein the analysis area is acquired by the constituted data satisfying a specified position relation with the constituted data of the reference image, and the displayed reference image and the analysis area satisfy the specified position relation; and when the reference image performs a dimension scaling, the analysis area performs a same dimension scaling based on a same base point, to remain a same dimension scale.