A stripping apparatus is described for the gas-solid separation process in a fluidized bed in a counter-current flow of a stripping fluid. The apparatus includes sets of perforated baffle-plates with holes, fixed in series, alternating central and lateral plates inside a stripping chamber. The holes in the baffle-plates, in number, size and in circular or elliptical lay-out, are oriented in offset position in relation to the holes in the parallel and subsequent baffle-plates, reducing the damage of erosion on the perforated baffle-plates and optimizing stripping of the fluidized solid particles.