PROBLEM TO BE SOLVED: To quickly retreat a top plate on which a subject is placed from inside a trestle in a bed device and a medical image diagnostic apparatus.SOLUTION: A bed device includes a bed body on which a top plate 51 is placed, the top plate 51 having a traveling roller 51a which rotates on the bed body, a traveling guide 51b for guiding traveling of the top plate on the bed body by being provided on the bed body and brought into contact with the top plate 51 or by being provided on the top plate 51 and brought into contact with the bed body, and an operation part 51c for performing operation for causing the travel guide 51b provided on the bed body to retreat to the bed body, or performing operation for causing the travel guide provided on the top plate to retreat to the top plate.SELECTED DRAWING: Figure 3【課題】寝台装置及び医用画像診断装置において、被検体を載置する天板を架台内部から速やかに退避させること。【解決手段】寝台装置は、天板５１を載置する寝台本体と、前記寝台本体の上で回転する走行ローラ５１ａを有する天板５１と、前記寝台本体に設けられて前記天板５１に接触させる、または前記天板５１に設けられて前記寝台本体に接触させることで、前記天板が前記寝台本体の上で走行するのをガイドする走行ガイド５１ｂと、前記寝台本体に設けられた前記走行ガイド５１ｂを前記寝台本体に退避させる操作、または前記天板に設けられた前記走行ガイドを前記天板に退避させる操作を行う操作部５１ｃと、を備えた。【選択図】図３
