Abstract: Disclosed is an ellipsograph for drawing an ellipse. A base member for defining one side, that is, a base of a triangle, is provided and fixed to a plane of a drawing sheet. A centering section and an ellipse drawing frame are installed at a middle of the base member. An ellipse deriving thread for determining the total length of three sides of the triangle which is used to draw the ellipse is prepared and supported by both ends of the base member and one end of the ellipse drawing frame thereby to form the triangle. The ellipse is drawn by the ellipse drawing frame while the ellipse drawing frame is rotated and linearly reciprocated due to the fact that the ellipse drawing frame is pressed by the ellipse deriving thread against elastic force of elastic spring and biased by the elastic spring against tension of the ellipse deriving thread.