The present disclosure relates to a safety apparatus for a ladder. Specifically, a safety apparatus for a ladder according to an embodiment of the present disclosure protects safety of a user who uses a ladder, and the safety apparatus includes a guard member provided to be mounted on the ladder and extending in one direction, and a plurality of fixing members connected to the guard member, disposed to be spaced apart from one another in a longitudinal direction of the guard member, and configured to fix the guard member to the ladder, in which the guard member has at least a part configured to protrude toward a rear side of the ladder and cover a rear surface of the ladder.