A tomographic image generating apparatus comprising: an image acquisition unit that acquires a plurality of projection images corresponding to a plurality of radiation source positions, the plurality of projection images being generated by causing an imaging apparatus to perform tomosynthesis imaging in which a radiation source is moved relative to a detection surface of a detection unit in order to emit radiation to a subject at the plurality of radiation source positions according to movement of the radiation source; a reconstruction unit that reconstructs all or a part of the plurality of projection images to generate a tomographic image on each of a plurality of tomographic planes of the subject; a feature point detecting unit that detects at least one feature point from a plurality of the tomographic images; a positional shift amount derivation unit that derives a positional shift amount between the plurality of projection images based on body movement of the subject using the feature point as a reference on a corresponding tomographic plane corresponding to the tomographic image in which the feature point is detected, wherein the reconstruction unit reconstructs the plurality of projection images by correcting the positional shift amount to generate a corrected tomographic image on at least one tomographic plane of the subject; and a projection unit that projects the plurality of projection images on the corresponding tomographic plane based on a positional relationship between the radiation source position and the detection unit in a case of imaging the plurality of projection images to acquire a tomographic plane projection image corresponding to each of the plurality of projection images, wherein the positional shift amount derivation unit derives, as the positional shift amount between the plurality of projection images, a positional shift amount between a plurality of the tomographic plane projection images based on the body movement of the subject using the feature point as a reference on the corresponding tomographic plane. an image acquisition unit that acquires a plurality of projection images corresponding to a plurality of radiation source positions, the plurality of projection images being generated by causing an imaging apparatus to perform tomosynthesis imaging in which a radiation source is moved relative to a detection surface of a detection unit in order to emit radiation to a subject at the plurality of radiation source positions according to movement of the radiation source; a reconstruction unit that reconstructs all or a part of the plurality of projection images to generate a tomographic image on each of a plurality of tomographic planes of the subject; a feature point detecting unit that detects at least one feature point from a plurality of the tomographic images; a positional shift amount derivation unit that derives a positional shift amount between the plurality of projection images based on body movement of the subject using the feature point as a reference on a corresponding tomographic plane corresponding to the tomographic image in which the feature point is detected, wherein the reconstruction unit reconstructs the plurality of projection images by correcting the positional shift amount to generate a corrected tomographic image on at least one tomographic plane of the subject; and a projection unit that projects the plurality of projection images on the corresponding tomographic plane based on a positional relationship between the radiation source position and the detection unit in a case of imaging the plurality of projection images to acquire a tomographic plane projection image corresponding to each of the plurality of projection images, wherein the positional shift amount derivation unit derives, as the positional shift amount between the plurality of projection images, a positional shift amount between a plurality of the tomographic plane projection images based on the body movement of the subject using the feature point as a reference on the corresponding tomographic plane.