Machines, cars suspensions, buildings steel constructions etc. usually generate vibrations, which can be the excitement signal for piezoelectric energy harvesters. The piezoelectric patches attached to the vibrating construction have ability to convert mechanical energy of harmful vibrations into electrical energy.The goal of the study was to verify a finite element model of the piezoelectric beam energy harvester by comparing results of numerical simulations with those obtained experimentally. The stand used in the experiment consists of the cantilever beam with piezoelectric elements attached, which is excited by the base harmonic movement. The transverse displacements of the selected beam’s point and the base, and also the frequency of vibrations were observed and measured using an accelerometer and a B&K Pulse platform. A portable data acquisition module was used to quantify the voltage generated by the piezoelectric layers.The finite element model was built in ANSYS software. The beam and piezoelectric layers were modeled by twenty node elements with an additional electric degree of freedom for piezoelectric elements. A full piezoelectric matrix was used in the finite element analysis instead of a one-dimensional piezoelectric effect, which dominates in many analytical approaches. It allowed building a more accurate model of the system. The experimental tests and finite element method simulations were performed and acquired results were compared. The characteristics of voltage amplitude in the time and frequency domain were shown and discussed.