Disclosed herein is a length adjustable skate blade guard. The blade guard includes a first guard surrounding at least portion of a lower surface of a skate blade and a front end of the skate blade. A second guard surrounds a remaining portion of the lower surface of the skate blade and a rear end of the skate blade. At least one extension block is coupled between the first guard and the second guard, and extends a length of the guard to correspond to a length of the skate blade. At least one elastic body is secured at opposite ends thereof to the first guard and the second guard, respectively, the elastic body elastically putting the facing first and second guards in close contact with each other.