Embodiments provide a filtering device, to effectively simplify assembly and tuning processes. The filtering device includes: a housing, including an inner cavity; a resonant conductor, having a resonance function, and disposed inside the inner cavity; and a pressing element, having one end disposed on the housing and another end suspended, and facing a position of an open-circuit end of the resonant conductor. A distance between the pressing element and the resonant conductor is changeable when the pressing element is pressed or drawn to adjust a resonant frequency. The filtering device provided in various embodiments is applicable to a plurality of communications devices for selecting a signal frequency.