1. A radiographic image analysis device that analyzes a subject image captured by irradiating a subject with radiation to estimate a body thickness distribution of the subject, the device comprising: an image acquisition unit that acquires the subject image; a model information acquisition unit that acquires model information, in which a model image captured by irradiating each of a plurality of models different from the subject with radiation is associated with a body thickness distribution of the model in the model image, for each of the plurality of models; and a body thickness distribution determination unit that acquires characteristic information indicating characteristics of the subject image, acquires characteristic information indicating the characteristics of each of the plurality of model images, on the basis of the plurality of model information items, specifies the model image having characteristic information similar to the characteristic information of the subject image, and determines the body thickness distribution associated with the specified model image as the body thickness distribution of the subject image.