Abstract: Proposed a novel Swash-Plate inerter, composed of a swash plate, crankshaft, planetary gear train, support disc, and flywheel. Achieved the inerter effect by forcing the swash plate to rotate via the crankshaft. Established the mechanical model of the swash-plate inerter, and analyzed the influence of structural parameters such as maximum displacement and swash plate inclination angle on its performance. Solved the dynamic response of a single-degree-of-freedom vibration isolation system incorporating the Swash-Plate inerter by the harmonic balance method. Investigated the effects of system parameters, including the inerter-mass ratio and damping ratio, on displacement transmissibility and compared with those of a linear inerter system. Examined the system’s performance under real-world vibrations. The results demonstrate that the Swash-Plate inerter exhibits nonlinear characteristics dependent on input displacement, with greater inertance under stronger vibrations. The analytical solutions for the system’s dynamic response align closely with numerical simulations. The vibration isolation system integrated with the Swash-Plate inerter exhibits reduced peak displacement and lower resonance frequency. Seismic excitation simulations further reveal that the proposed inerter is particularly suitable for scenarios with relatively fixed vibration frequencies and narrow frequency bandwidths.