[Problem] To provide a puncture device and a method for implanting a cannula, whereby a cannula can be reliably implanted in a living body. [Solution] A puncture device has: a main body 10 capable of being affixed to the surface of a living body； a puncture needle provided with a cannula and an inner needle inserted in the cannula； a housing for accommodating the puncture needle； a puncture mechanism for performing a puncture operation for making it possible to withdraw the inner needle from the main body with the cannula still protruding after the puncture needle is caused to protrude from the main body, the puncture mechanism being provided in the housing； and a fixing mechanism 120 for fixing the cannula to the main body in a state in which the puncture needle is caused to protrude from the main body. The puncture mechanism is provided with a puncture needle retaining part including a first retaining part 130 and a second retaining part for retaining the inner needle, and an urging member for imparting to the puncture needle retaining part an urging force in the protrusion direction in which the puncture needle is caused to protrude from the main body. The fixing mechanism is provided with an engaging part 150 for engaging the first retaining part with the main body in conjunction with the operation whereby the first retaining part moves relative to the main body in a direction other than the protrusion direction.【課題】生体に対してカニューレを確実に留置できる穿刺装置およびカニューレの留置方法を提供することである。【解決手段】穿刺装置は、生体表面に貼り付け可能な本体部１０と、カニューレとカニューレ内に挿入された内針とを備える穿刺針と、穿刺針を収容する筐体と、筐体内に設けられ、穿刺針を本体部から突出させた後、カニューレを突出させたまま、内針を本体部から抜去可能にする穿刺動作を行う穿刺機構と、穿刺針が本体部から突出された状態においてカニューレを本体部に固定する固定機構１２０と、を有する。穿刺機構は、カニューレを保持する第１保持部１３０および内針を保持する第２保持部を含む穿刺針保持部と、穿刺針を本体部から突出させる突出方向の付勢力を穿刺針保持部に付与する付勢部材と、を備える。固定機構は、第１保持部が本体部に対して突出方向とは異なる方向に相対的に移動する動作に伴って当該第１保持部を当該本体部に係合する係合部１５０を備える。【選択図】図２０
