An insertion device includes a cover body, an insertion module. The insertion module is disposed in the cover body, and includes a main body, an insertion seat, a first elastic member, a retraction seat and a second elastic member. When the cover body is depressed, the insertion seat is driven by the first elastic member to perform an automatic-insertion operation and to collapse a limiting structure between the insertion seat and the cover body. A limiting structure between the insertion seat and the retraction seat collapses upon the collapse of the limiting structure between the insertion seat and the cover body, so that the retraction seat is driven by the second elastic member to perform an automatic-retraction operation.