A sheet manufacturing apparatus includes a first frame on which an accumulation belt and a first suction unit are installed and a second frame on which a transport belt and a second suction unit are installed. An eccentric cam is disposed between the first frame and the second frame. A position of the second frame with respect to the first frame is changed by rotation of the eccentric cam.

A sheet manufacturing apparatus includes a defibrator that defibrates a paper piece to form a defibrated material, an accumulator that accumulates the defibrated material on a mesh belt to form an accumulating material, a forming machine that forms the transported accumulating material to produce a strip-shaped sheet, and a return mechanism that sends a residual accumulating material that is the defibrated material being accumulating to the defibrator on condition that the accumulator has stopped or is stopped during accumulation.

A sheet manufacturing apparatus includes a defibrator that defibrates a paper piece to form a defibrated material, an accumulator that accumulates the defibrated material on a mesh belt to form an accumulating material, a forming machine that forms the transported accumulating material to produce a strip-shaped sheet, and a return mechanism that sends a residual accumulating material that is the defibrated material being accumulating to the defibrator on condition that the accumulator has stopped or is stopped during accumulation.