A sheet manufacturing apparatus includes a defibration unit and a sheet forming unit. The defibration unit includes a rotating unit and a housing including a cover portion and a fixing unit attached to the cover portion and spaced apart from the rotating unit in a direction perpendicular to an axial direction of the rotating unit so as to form a gap between the rotating unit and the fixing unit. The defibrating unit is configured to cause the rotating unit to rotate and dry-defibrate a defibration object. The sheet forming unit is configured to form a sheet by depositing defibrated material. The rotating unit includes rotating plates base sections located on a side of a central rotation axis and protruding sections protruding out in a direction drawing away from the central rotation axis, and the rotating plates is stacked such that the protruding sections are in contact in the axial direction.