PROBLEM TO BE SOLVED: To provide a medical device which enables a plurality of operations to be performed by a single operation and has excellent operability.SOLUTION: The medical device comprises: a catheter 1 to be inserted into a living body； a holding part 20 and a needle positioning part 61 arranged within the catheter 1 so as to be moved back and forth； a sliding part 100 which can be operated so as to simultaneously move the holding part 20 and the needle positioning part 61 back and forth； and an operation switching part 130 which makes back and forth movement of the holding unit 20 be linked with or independent from the sliding part 100 in accordance with the back and forth movement of the sliding unit 100.【課題】複数の動作を１つの操作で行うことができ、操作性に優れた医療用デバイスを提供する。【解決手段】生体内に挿入されるカテーテル１と、前記カテーテル１内に進退動可能に配置される挟持部２０および針位置決め部６１と、挟持部２０および針位置決め部６１を同時に進退動するように操作可能なスライド部１００と、挟持部２０の進退動を、スライド部１００の進退動に起因して当該スライド部１００に対して連動または独立させる動作切換部１３０と、を有する医療用デバイスである。【選択図】図９
