A horizontal dry mill comprising: a grinding tank having a tubular grinding chamber, and a tubular raw material supply section continuously connecting to the grinding chamber to supply a raw material to the grinding chamber, a diameter of the raw material supply section being set to be less than a diameter of the grinding chamber; a raw material input section provided at one end of the grinding tank; a raw material discharge section provided at the other end of the grinding tank via a media separation member; grinding media set in the grinding chamber; a horizontal, rotational driving shaft extending in the raw material supply section and the grinding chamber of the grinding tank; a raw material supply member disposed in the raw material supply section and attached to the horizontal, rotational driving shaft, the raw material supply member being configured to supply the raw material input into the raw material supply section from the raw material input section, to the grinding chamber, while being rotationally driven by the horizontal, rotational driving shaft, the raw material supply member being a mechanical thrust generating device configured to be rotated to thereby give, to the raw material input from the raw material input section, thrust toward the grinding chamber, a diameter of said mechanical thrust generating device being set to a small value according to the diameter of the raw material supply section, so as to prevent blow-up of the raw material input from the raw material input section into the raw material supply section; and an agitation member disposed in the grinding chamber and attached to the horizontal, rotational driving shaft, the agitation member being configured to agitate the raw material supplied from the raw material supply section, while being rotationally driven by the horizontal, rotational driving shaft, wherein the mechanical thrust generating device is a screw, characterised in that a radially-outer end of the screw is formed in a sharp shape by providing an acute-angled inclined relief surface, on a side opposite to a transport surface of the screw. a grinding tank having a tubular grinding chamber, and a tubular raw material supply section continuously connecting to the grinding chamber to supply a raw material to the grinding chamber, a diameter of the raw material supply section being set to be less than a diameter of the grinding chamber; a raw material input section provided at one end of the grinding tank; a raw material discharge section provided at the other end of the grinding tank via a media separation member; grinding media set in the grinding chamber; a horizontal, rotational driving shaft extending in the raw material supply section and the grinding chamber of the grinding tank; a raw material supply member disposed in the raw material supply section and attached to the horizontal, rotational driving shaft, the raw material supply member being configured to supply the raw material input into the raw material supply section from the raw material input section, to the grinding chamber, while being rotationally driven by the horizontal, rotational driving shaft, the raw material supply member being a mechanical thrust generating device configured to be rotated to thereby give, to the raw material input from the raw material input section, thrust toward the grinding chamber, a diameter of said mechanical thrust generating device being set to a small value according to the diameter of the raw material supply section, so as to prevent blow-up of the raw material input from the raw material input section into the raw material supply section; and an agitation member disposed in the grinding chamber and attached to the horizontal, rotational driving shaft, the agitation member being configured to agitate the raw material supplied from the raw material supply section, while being rotationally driven by the horizontal, rotational driving shaft, wherein the mechanical thrust generating device is a screw, characterised in that a radially-outer end of the screw is formed in a sharp shape by providing an acute-angled inclined relief surface, on a side opposite to a transport surface of the screw.