[Problem] To provide an endless track link and an endless track belt which have improved torsional fatigue strength while suppressing the weakening of the entire link. [Solution] This endless tack link 1 is provided with a bushing hole 7, a window hole 12, a roller tread surface 16, and a rear plate mounting surface 15, wherein, when viewed from the side, among portions except for the roller tread surface, at least a portion of a region surrounded by: (A) a line segment SL1 connecting a bushing hole side-end of the bottom surface of the window hole with a bushing hole side-end of the rear plate mounting surface; (B) an upper tangent line TL1 tangent to each of the outer circumferential edges at the sides of the bushing hole and the window hole, the sides being the closest to the roller tread surface; (C) a horizontal line HL1 at the side opposite to the window hole, among horizontal lines which pass through the center of the bushing hole and are parallel to the rear plate mounting surface; (D) the window hole
