Abstract: Disclosed herein is a buoy having a means for self-generating electricity using wave power. The buoy includes a float body floating on the sea, and a lower actuating unit extending though a hole formed at the center portion of the float body in such a way as to be vertically set through the body and rectilinearly reciprocating through the body in a vertical direction due to a difference in a moving velocity between the float body and the actuating body when the body is moved by waves. An electric generator is mounted on the float body and generates electric energy by a rotating force generated by conversion of a vertical reciprocating movement of the lower actuating unit into a rotating movement of a pinion engaging with a rack formed along the upper portion of the actuating unit. An upper support unit is installed on the float body for supporting the lower actuating unit. The buoy also has a lamp indicating a position of the buoy using the electric energy generated by the electric generator.