Abstract: The invention relates to a method for making the drying finely divided materials, more effective in a suction drier provided with a fine porous suction surface, where the radii of the fine pores of the suction surface are essentially within the range of 0.5-2 micrometers, and in which method, of a slurry containing liquid and solids there is made a filter cake (2,12,22) onto a fine porous liquid suction surface constituting the filter surface of the filter medium (1,11,21), According to the invention, the filter cake (2,12,22) and an oscillator (6,15,25) are arranged, in relation to each other, so that in between the filter cake (2,12,22) and the oscillator (6,15,25), there is generated an acoustic field by virtue of a mechanical contact between the filter cake (2,12,22) and the oscillator (6,15,25) or a structural element (7,16,26) connected to the oscillator.