Abstract: The invention relates to a securing pin (16) which, in order to secure two chain connector shackles (12, 14) of a chain connector (10) against becoming disengaged, can be inserted into an opening (28) formed by the two chain connector shackles (12, 14), comprising a base body (30) with a through-hole (32), at least one spring ring (34), at least two balls (36), and a securing member (38) inserted into the through-hole (32), wherein an annular groove (54) in which the spring ring is inserted (34) is provided in a lateral surface (59) of the base body (30), wherein the annular groove (54) is provided with two bore holes (66) which are aligned with the through-hole (32) and in which the balls (36) rest, and wherein the spring ring (34) has at least one leg (64) which extends in the longitudinal direction of the base body (30) and which bends out of shape if the securing pin (16) is inserted into the opening (28) incorrectly.