A compact antenna apparatus for a mobile communication system includes: a radome having at least one frequency band radiating element provided therein; at least one phase shifter portion which is provided in an inner side of the radome and which is connected to the radiating element to adjust a tilting angle of the radiating element; and a rotary knob portion which is provided so as to be exposed to the outside of the radome and which is directly coupled to the phase shifter portion to drive a phase shifter.