The x-ray photographing device which does not have the fact that with phototimer photographing the body of the suffering inspection person because thick is thick the x-ray morphism stops with back up time and becomes underexposure is offered. Database section 18 keeps the body thick t of various suffering inspection people M and x-ray condition and the database which shows the relationship of photographing time. Search processing section 16 searches the data which agrees to the x-ray condition which is retained in conditional retention section 15 and the body thick t which was calculated in body thick measurement section 17 with the aforementioned database and calculates the photographing time which corresponds. When it is longer than the back up time where the said photographing time is set to x-ray controller 12, search processing section 16 indicates the fact that back up time is made to extend to the said photographing time to x-ray controller 12. When x-ray controller 12 extends back up time, through high-voltage generator 13 under the x-ray conditions for being retained in conditional retention section 15 the x-ray shines, receives the x-ray cutoff signal from phototimer 11 the morphism of the x-ray is stopped and photographing ends.ホトタイマ撮影で被検者の体厚が厚いためにバックアップタイムでX線曝射が停止し露出不足となることのないX線撮影装置を提供する。データベース部18は多様な被検者Mの体厚tとX線条件と撮影時間の関係を示すデータベースを保持する。検索処理部16は条件保存部15に保存されたX線条件と体厚計測部17で算出された体厚tに一致するデータを前記データベースで検索し対応する撮影時間を求める。該撮影時間がX線制御器12に設定されているバックアップタイムより長い場合、検索処理部16はバックアップタイムを該撮影時間まで延長させることをX線制御器12へ指示する。X線制御器12はバックアップタイムを延長し、条件保存部15に保存されているX線条件で高電圧装置13を介してX線を曝射し、ホトタイマ11よりX線遮断信号を受信するとX線の曝射を停止し撮影を終了する。
