According to one embodiment, a radiation diagnostic apparatus includes an X-ray tube, radiation detecting elements, signal processing substrates, and processing circuitry. The signal processing substrates performs processing including at least A/D conversion processing on outputted signals of the radiation detecting elements and outputs processed signals as the outputted signals subjected to the processing. The processing circuitry identifies a non-observing element or a non-observing substrate based on information on an imaging region included in imaging conditions of an object, the non-observing element being a radiation detecting element of the radiation detecting elements which corresponds to a region other than the imaging region, and the non-observing substrate being a signal processing substrate of the signal processing substrates which corresponds to the non-observing element. The processing circuitry further controls an operation of the non-observing element or an operation of the non-observing substrate in imaging under the imaging conditions.
