To obtain a fiber reinforced thermoplastic resin sheet uniform in the adhesion amt. of a resin, uniform in wall thickness in its lateral direction and having good surface smoothness, in a method for producing the fiber reinforced thermoplastic resin sheet used in the molding of a fiber reinforced resin molded product, by applying vibration to upper and lower powdery thermoplastic resin bonded fiber bundles in a lateral direction when the fiber bundles are superposed under heating and pressure.

Powdery resin bonded fiber bundles 2, 2 are guided from two upper and lower systems and the upper resin bonded fiber bundles 2 are heated from the upper surface side thereof while the upper surface side thereof is pressed by an upper press member and the lower resin bonded fiber bundles 2 are heated from the rear surface side thereof while the rear surface side thereof is pressed by a lower press member to superpose the upper and lower resin bonded fiber bundles 2, 2 and, at this time, the both fiber bundles 2, 2 are superposed one upon another laterally to uniformly disperse unmelted or molten powdery resins 4, 4 on a superposed surface side opposite to a heated surface.