A multi-band antenna apparatus according to one of various embodiments of the present invention may comprise: an antenna housing in which an antenna module having two or more frequency bands is mounted; a plurality of repeaters detachably coupled to the antenna housing according to slide movement thereof; connector parts which protrude from the antenna housing and are connected to the plurality of repeaters, respectively; and a bracket which fixes the antenna housing to an outer wall and couples the plurality of repeaters to the antenna housing in an individually detachable manner.