Based on the metal nanodisks arranged in the longitudinal configuration and their coupled localized surface plasmon resonances, a simple optical nanofilter is designed and fabricated using the hole-mask nanolithography technique. The filtering and physical concepts of the nanostructure are discussed using the quasi-static approximation and the circuit model. The optical properties of the proposed nanofilter are investigated using the dispersive finite­difference time-domain method. The spectral response of the filter is tunable in the considered optical range. The model and simulations results agree with the experiments.