An engagement chain includes a pair of first and second chain members that are engaged so as to be integrated with each other by moving in an advancing direction and disengaged from each other so as to bifurcate by moving in a retreating direction from the integrated engaged state. A first link plate of the first chain member includes first and second pin holes through which a coupling pin is inserted. A second link plate of the second chain member includes first and second pin holes through which a coupling pin is inserted. A first distance between the first and second pin holes of the first link plate is shorter than a second distance between the first and second pin holes of the second link plate.