To provide a biomass mill of improved crushing efficiency and an increased crushing capacity attained by aggressively discharging crushed wood biomass therefrom.

The biomass mill including a housing 3 wherein a classifying chamber 16 is formed, a classifier 32 stored in the upper part of the housing 3, a crushing table 5 driven by a table-driving device 6 and stored in the lower part of the housing 3, a pressure roller unit 9 comprising a pressure roller 11 pressed onto the crushing table 5, a primary air chamber 15 formed underneath the crushing table 5, for primary air to be introduced thereinto, an air-blowing port 18 for blowing the primary air present in the primary air chamber 15 from the circumference of the crushing table 5, and a chute 21 for feeding wood biomass onto the center of the crushing table 5, is characterized in that the air-blowing port is formed perpendicular or with a tilt in the reverse direction relative to the rotation direction of the crushing table 5 so as to decrease the swirl flow of the primary air.