Use of a vibratory feeder is commonly seen in mass prcduction fields for conveyance of machine parts or particles such as raw materials. However, the principle how these particles are conveyed by vibratory motions, has not been thoroughly investigated. In this paper the motion of the particle fed by a sinusoidally oscillating plate of feeder is studied from a dynamical view point. The particle or the part is assumed to be a mass point for simplicity of analysis. When the amplitude of oscillation is small, the particle is conveyed by gliding motion on the surface of the vibrating plate. When the amplitude exceeds a certain value, the particle jumps up from the surface of the plate, so that in this case the procedure of feeding differs from that of a jumpless case. Analysis covering both cases is carried out and the validity is demonstrated experimentally.