While preventing the decrease of resolution, utilizing the indicatory territory effectively, in order to offer the x-ray diagnostic device which can indicate the x-ray picture, as for x-ray diagnostic device 1, x-ray generator the x-ray contraction expedient 12 where stipulates the lighting range of 11 and the x-ray and x-ray plane surface detector the radiation field territory detection expedient the detection position candidacy point calculation expedient which is calculated information of position of the candidacy point of detection position of the rectangular territory which is circumscribed to the radiation field territory in 21 which detects the information of position of the radiation field territory of the x-ray for 13 and x-ray plane surface detector 13 and the picture, on the basis of the information of position of the radiation field territoryThe rectangular region calculation expedient the rectangular territory indicatory expedient 26 which indicates 24 which calculates the information of position of the rectangular territory on the basis of the information of position of 23 and the candidacy point and the rectangular territory and, it has.解像度の低下を防ぎつつ、表示領域を有効活用してX線画像を表示できるX線診断装置を提供するために、X線診断装置1は、X線発生器11と、X線の照射範囲を規定するX線絞り手段12と、X線平面検出器13と、X線平面検出器13に対するX線の照射野領域の位置情報を検出する照射野領域検出手段21と、画像における照射野領域に外接する矩形領域の切り出し位置の候補点の位置情報を、照射野領域の位置情報に基づいて算出する切り出し位置候補点算出手段23と、候補点の位置情報に基づいて矩形領域の位置情報を算出する矩形領域位置算出手段24と、矩形領域を表示する矩形領域表示手段26と、を備える。
