NOVELTY - The biomass processing device comprises a conveying device (2) and a drying device (3). A heat dissipation channel (3a) of the drying device is connected with a heat supply channel (2a) of the conveying device to conduct heat from the drying device in a conveying direction. The drying device has a rolling bed dryer for uniform drying and mixing wood, preferably for thinning wood. The conveying device comprises a heat-permeable area, on which the biomass is provided. The device further comprises a defibring unit, a separating device (5), and a buffer arranged at the separating device.    USE - The biomass processing device is useful for thinning wood (claimed), wood shavings, wood chips, Miscanthus giganteus, and other biomass-producing plants such as shrubs (Pyracantha and blackberry), where the wood comprises energy woods or hardwoods such as chestnut, birch and beech, and softwoods such as yew, spruce and firs, and the thinned wood is useful in a device for producing thermal energy.    ADVANTAGE - The biomass processing device economically thins the wood, and ensures the high combustion temperature of the biomass in order to avoid pollution and to increase the efficiency of combustion.    DETAILED DESCRIPTION - The biomass processing device comprises a conveying device (2) and a drying device (3). A heat dissipation channel (3a) of the drying device is connected with a heat supply channel (2a) of the conveying device to conduct heat from the drying device in a conveying direction. The drying device has a rolling bed dryer for uniform drying and mixing wood, preferably for thinning wood. The conveying device comprises a heat-permeable area, on which the biomass is provided. The biomass processing device further comprises a defibring unit, a separating device (5), and a buffer, which is arranged at the separating device. The defibring unit comprises a mill fiberized biomass. The separating device comprises a sieve such as tumble screen for the separation of wood fibers and wood dust, and an optical unit for the optical resolution in the separation of wood fibers and wood dust. An INDEPENDENT CLAIM is included for a biomass processing method.    DESCRIPTION OF DRAWING(S) - The figure shows a block diagram of a biomass processing device (Drawing includes non-English language text).    Conveying device (2)    Heat supply channel (2a)    Drying device (3)    Heat dissipation channel (3a)    Separating device. (5)