The grain dryer according to the present invention, an external inlet pipe which is a passage for the external wind blower from the outside, a blower connected to the external inlet pipe and a discharge pipe connected to the blower to discharge wind, and connected to the discharge pipe A double helix tube coupled to the distal end of the discharge pipe and heat-exchanged with each other, a body connected to the double helix tube and having a predetermined internal space, and connected to the upper part of the body to be connected to the inside of the body to obtain hot dry air in the lower part of the body. Hot air inlet pipe to send a, and the upper part of the body through the insulated tube to pass through the inner and forming a double helix tube to make a double insulated, the lower part of the double helix tube passed through a double helix tube It forms a heat insulated tube to allow cold air and condensate to flow out. The body is made of opening and closing door for opening and closing the grain, and the body and the opening and closing door to the interior of the wall and the interior, the shelf to put the grain into the body, and put the grain to be dried on the shelf On top of the mesh body, the inner bottom of the body is an electric heating element that can heat the air inside, the outer right side of the body is attached to the top of the thermostat to automatically control the air temperature of the body and to drive the electric heating element and the blower The temperature controller may have a built-in temperature sensor, and may include an electric heating element, a temperature controller, and a blower to configure a wire part. In addition, the opening and closing door may further include an elastic packing and a hinge and a locking device to shield heat from escaping from the inside of the body. In addition, the sensor of the outer right side temperature controller outside the body may be characterized in that the temperature is introduced int
