In order to realize a long-lived electric propulsion system, we have been investigating an electrodeless plasma thruster concept utilizing a helicon plasma source and Lissajous plasma acceleration, which uses the static diverging magnetic field and a rotating electric field (REF). Using a laboratory model of the Lissajous acceleration-type thruster, plasma acceleration experiments have been conducted. In the experiments, plasma flow velocity was measured at the center in the thruster using a para-perp type Mach probe. It was observed that the application of the REF power (13.56 MHz, 1.4kVp-p) makes in increase in the plasma flow velocity. In addition, axial distributions of the plasma velocity indicate that the particle collision between neutral gas and plasma particle has a significant effect on the plasma expansion process in the magnetic nozzle.