A fibrous material accumulating apparatus includes a dispersing section which disperses a material containing fibers, a belt which accumulates the dispersed material, and a suction section provided on a side of the belt opposite to the dispersing section, in which the dispersing section includes a storage section including a screen, a supply section which supplies the material to the storage section, and a rotating body which is provided inside the storage section and agitates the material supplied into the storage section, and the storage section includes a communicating port which causes an inside and an outside of the storage section to communicate with each other and is provided at a different position from the screen.