A tunable filter device that changes a central frequency and a bandwidth is provided. The tunable filter device may include a body forming a cavity together with a cover, a resonator attached to or integrally formed on a lower surface of the cavity, a frequency-tuning element including a head and a shaft, the shaft passed through the cover and inserted in the resonator, and a cam disposed on the head to contact the head, wherein an insertion length of the shaft is controlled by the cam.