The sheet manufacturing apparatus includes a defibrating unit configured to defibrate a defibration object in the air, and a sheet forming unit configured to form a sheet by using at least a part of defibrated material that has been defibrated by the defibrating unit. The flow path configured to transfer the defibration object to the defibrating unit has a pipeline unit through which the defibration object passes, an opening having a size through which the defibration object does not pass on a surface of the pipeline unit, and an enclosure unit enclosing the pipeline unit such that the opening is positioned inside.