Sealing element for terminal, manufacturing method thereof and connector comprising sealing element

The invention provides a sealing element for a terminal, which has a simple structure, is easy to assemble, is manufactured at low cost, can hold the terminal in a sliding manner while surely maintaining liquid tightness and air tightness, surely maintains a conduction state between the terminal and a mating terminal of a mating connector, and improves reliability. A sealing element for a terminal includes a shaft portion and a flange provided on the shaft portion, the sealing element for the terminal being attached to a terminal (51) slidable in a front-back direction, the sealing element for the terminal including: a pressing element attached around the shaft portion and pressing the flange forward; an elastic cylinder member including a center hole into which the shaft portion can be slidably inserted and into which the pressing member is embedded; and an elastic attachment member including a center hole into which the shaft portion is slidably inserted and attached to both front and rear ends of the elast