Provided is an insertion device whereby an operating force inputted to a slide member via a transmission member is efficiently transmitted to a functional part, and a desired function is reliably obtained. An endoscope (1) is provided with: a slide member (53) provided with an input part to which an operating force for causing movement in the direction of a longitudinal axis (53a) is inputted； a shaft member (54) provided in a position separated from the input part in the slide member (53) and having a shaft (54a) intersecting with the longitudinal axis (53a)； a link mechanism part (55) provided so as to be able to rotate about the shaft member (54), the link mechanism part (55) being moved in conjunction with movement of the slide member (53) in the direction of the longitudinal axis (53a), rotating about the shaft member (54), and converting the direction of a force acting in the direction of the longitudinal axis (53a)； a fixing function part (56) for receiving the force converted by the mechanism part (55) and functioning； and a restricting member (60) for restricting movement of the slide member (53) in an intersecting direction at the movement position of the slide member (53) when the mechanism (55) applies force to the fixing function part (56) in conjunction with the movement of the slide member (53).La présente invention concerne un dispositif d'insertion par lequel une force de fonctionnement appliquée à un élément coulissant par l'intermédiaire d'un élément de transmission est transmise efficacement à une partie fonctionnelle, et une fonction souhaitée est obtenue de manière fiable. Un endoscope (1) est pourvu : d'un élément coulissant (53) pourvu d'une partie d'entrée à laquelle une force de fonctionnement pour provoquer un mouvement dans la direction d'un axe longitudinal (53a) est appliquée； un élément d'arbre (54) prévu dans une position séparée de la partie d'entrée dans l'élément coulissant (53) et ayant un arbre (54a) en intersection avec l'axe lo
