Desktop loose-leaf base, and binder

A desk leaf base, comprising:

• a three-dimensional trapezoidal base member;
• and
• a binder, formed on a top portion of the three-dimensional trapezoidal base member, wherein the binder includes an elongated body, and a plurality of rings mounted on the body and capable of opening and closing;
• wherein each of the plurality of rings includes linear portions that protrude from the body so as to extend inclining upward on both sides of the body when closed;
• wherein the three-dimensional trapezoidal base member is a base formed of a trapezoidal tubular body, the tubular body being formed in a trapezoidal shape in a side view, closed from a bottom surface to a certain height in both sides, and opened in an upper portion therefrom, an inclined front wall of the tubular body being removed from one side to an other side, in a range from the certain height to a height higher than the certain height and lower than a top surface;
• wherein the binder is mounted along an elongated top surface of the base member;
• and
• wherein the elongated body of the binder is mounted along the top surface of the base member with an approximately same width as the top surface.