A sheet manufacturing apparatus includes a defibrating unit configured to defibrate a defibration object including at least a fiber, in air. The sheet manufacturing apparatus forms a sheet by adding a quantity of heat to a defibrated material defibrated at the defibrating unit. The sheet manufacturing apparatus includes a measuring unit configured to acquire moisture amount information of the defibrated material or the defibration object, and a controller configured to control the quantity of heat to be added to the defibrated material on the basis of the moisture amount information.