A bulk acoustic resonator filter includes: a series bulk acoustic resonator electrically connected, in series, between first and second ports through which a radio frequency (RF) signal passes; a second shunt bulk acoustic resonator, electrically shunt connected between the series bulk acoustic resonator and a ground and having a resonance frequency lower than that of the series bulk acoustic resonator; and a first shunt bulk acoustic resonator electrically connected to the second shunt bulk acoustic resonator in series and having a resonance frequency higher than that of the second shunt bulk acoustic resonator. One or both of the series bulk acoustic resonator and the first shunt bulk acoustic resonator includes a first electrode disposed above a substrate; a piezoelectric layer disposed on the first electrode; a second electrode disposed on the piezoelectric layer; and a trench formed in an upper surface or above the second electrode and recessed downwardly.