Experiments on boundary layer separation control by Magnetohydrodynamic (MHD) acceleration of a near-wall flow were conducted in M=1.5 supersonic flow. In the test section, the boundary layer separation was produced in front of a forward-facing step installed at the downstream of the test section. 19 pairs of electrodes were flush-mounted on a wall where the step was placed. Magnetic field was applied perpendicularly to the wall to accelerate the flow near the wall by the Lorentz force. Change of the boundary layer separation bubble was observed using a high-speed camera. The size of the separation bubble was reduced about 10% by applying the MHD interaction. Therefore possibility to control the boundary layer separation by the MHD interaction was experimentally demonstrated.