A method of fabricating a multi-band filter module is provided. The method includes forming a Film Bulk Acoustic Resonator (FBAR) on a piezoelectric substrate by forming a resonant part on the piezoelectric substrate and then an air gap recessed on a surface of the piezoelectric substrate and positioned under the resonant part; and forming a Surface Acoustic Wave (SAW) device on the piezoelectric substrate in which the steps of forming the FBAR and the SAW are concurrently performed.