Resonant properties of the three-layer metallic cantilevers with 40 nm thickness are investigated. Two types of the nanocantilevers were fabricated: Cr-Al-Cr and Ti-Al-Ti. Resonant frequencies of the nanocantilevers were determined from the experimentally obtained resonant curves. Cantilever oscillations were excited by the electric force, the registration of the cantilever motion was performed by the optical lever method. Dependencies of the first and the second resonant frequencies on the cantilever length and width were experimentally obtained. The experimental data analysis and the comparison with the theoretical predictions were performed. Relations between the cantilever resonance properties and its dimensions and material are discussed.