PROBLEM TO BE SOLVED: To provide a catheter for diagnostic imaging in which a guide wire can be easily inserted into a side branch or the like of a living body lumen and which is improved in deliverability within the living body lumen. A sheath (100) of an imaging catheter (10) is provided with a distal insertion portion (110) formed with a first guide wire lumen (113) through which a first guide wire (W1) can be inserted, and an axial direction relative to the distal insertion portion. The insertion portion 120, which is disposed on the proximal end side and has the imaging lumen 123 into which the imaging shaft 300 having the imaging unit provided at the distal end portion is formed, and the proximal end side in the axial direction with respect to the distal side insertion portion. And a proximal end side insertion portion 130 in which a second guide wire lumen 133 is formed and through which the second guide wire W2 can be inserted, and the insertion portion enables acquisition of a diagnostic image by the imaging unit. The observation window portion is formed on the distal side of the proximal end side insertion portion, and the central axis C1 of the first guide wire lumen is imaged on the cross section orthogonal to the axis of the sheath. for It is disposed at a position overlapping the Men. [Selection diagram] Fig. 6【課題】生体管腔の側枝等へガイドワイヤを容易に挿入することができるとともに生体管腔内での送達性が向上された画像診断用カテーテルを提供する。【解決手段】画像診断用カテーテル１０のシース１００は、第１のガイドワイヤＷ１が挿通可能な第１のガイドワイヤルーメン１１３が形成された先端側挿通部１１０と、先端側挿通部よりも軸方向の基端側に配置され、先端部に撮像ユニットが設けられた撮像シャフト３００が挿入される撮像用ルーメン１２３が形成された挿入部１２０と、先端側挿通部よりも軸方向の基端側に配置され、第２のガイドワイヤＷ２が挿通可能な第２のガイドワイヤルーメン１３３が形成された基端側挿通部１３０と、を有し、挿入部は、撮像ユニットによる診断画像の取得を可能にする観察用窓部１２５を有し、観察用窓部は、基端側挿通部よりも先端側に形成され、第１のガイドワイヤルーメンの中心軸Ｃ１は、シースの軸直交断面上において、撮像用ルーメンと重なる位置に配置されている。【選択図】図６
