An X-ray diagnosis apparatus comprising: an X-ray tube that generates X-rays; an X-ray detector that detects X-rays generated by the X-ray tube; an operating unit that instructs performance of moving picture imaging using the X-ray tube and the X-ray detector; and an X-ray condition determining unit that determines a condition of X-ray irradiation by the X-ray tube, wherein the X-ray condition determining unit is configured to: determine a focal-spot size of X-rays in a second moving picture imaging session performed in accordance with an operation input to the operating unit after a first moving picture imaging session, based on X-ray conditions in the first moving picture session, the X-ray conditions in the first moving picture session adjusted through feedback control are determined from an X-ray image generated by an output of the X-ray detector in the first moving picture imaging session performed in accordance with an operation input to the operating unit; and determine a focal-spot size of X-rays in third moving picture imaging session performed in accordance with an operation input to the operating unit after the second moving picture imaging session, based on X-ray conditions in the second moving picture session, the X-ray conditions in the second moving picture session adjusted through feedback control are determined from an X-ray image generated by an output of the X-ray detector in the second moving picture imaging session, wherein, during the first and second moving picture imaging sessions, the X-ray conditions are controlled in accordance with a change in the thickness of the subject by the feedback control. an X-ray tube that generates X-rays; an X-ray detector that detects X-rays generated by the X-ray tube; an operating unit that instructs performance of moving picture imaging using the X-ray tube and the X-ray detector; and an X-ray condition determining unit that determines a condition of X-ray irradiation by the X-ray tube, wherein the X-ray condition determining unit is configured to: determine a focal-spot size of X-rays in a second moving picture imaging session performed in accordance with an operation input to the operating unit after a first moving picture imaging session, based on X-ray conditions in the first moving picture session, the X-ray conditions in the first moving picture session adjusted through feedback control are determined from an X-ray image generated by an output of the X-ray detector in the first moving picture imaging session performed in accordance with an operation input to the operating unit; and determine a focal-spot size of X-rays in third moving picture imaging session performed in accordance with an operation input to the operating unit after the second moving picture imaging session, based on X-ray conditions in the second moving picture session, the X-ray conditions in the second moving picture session adjusted through feedback control are determined from an X-ray image generated by an output of the X-ray detector in the second moving picture imaging session, determine a focal-spot size of X-rays in a second moving picture imaging session performed in accordance with an operation input to the operating unit after a first moving picture imaging session, based on X-ray conditions in the first moving picture session, the X-ray conditions in the first moving picture session adjusted through feedback control are determined from an X-ray image generated by an output of the X-ray detector in the first moving picture imaging session performed in accordance with an operation input to the operating unit; and determine a focal-spot size of X-rays in third moving picture imaging session performed in accordance with an operation input to the operating unit after the second moving picture imaging session, based on X-ray conditions in the second moving picture session, the X-ray conditions in the second moving picture session adjusted through feedback control are determined from an X-ray image generated by an output of the X-ray detector in the second moving picture imaging session, wherein, during the first and second moving picture imaging sessions, the X-ray conditions are controlled in accordance with a change in the thickness of the subject by the feedback control.