Provided is a sheet manufacturing apparatus capable of desirably adjusting the thickness of the sheet, and forming sheets with highly uniform thickness or grammage. A sheet manufacturing apparatus configured to make a sheet from defibrated material of defibrated paper includes: a drum unit having a cylinder with a defibrated material storage space inside and multiple openings through which the defibrated material passes formed in the outside of the cylinder; an accumulator configured to accumulate the defibrated material that past the openings, forming a deposit; and a housing configured to enclose the drum unit and the accumulator, the housing having a vent through which air passes between the drum unit and the accumulator.

Provided is a sheet manufacturing apparatus capable of desirably adjusting the thickness of the sheet, and forming sheets with highly uniform thickness or grammage. A sheet manufacturing apparatus configured to make a sheet from defibrated material of defibrated paper includes: a drum unit having a cylinder with a defibrated material storage space inside and multiple openings through which the defibrated material passes formed in the outside of the cylinder; an accumulator configured to accumulate the defibrated material that past the openings, forming a deposit; and a housing configured to enclose the drum unit and the accumulator, the housing having a vent through which air passes between the drum unit and the accumulator.