Provided is a motion guide device, which alleviates a tensile force acting on a holding belt when the holding belt circulates in an endless circulation path together with rolling elements, thereby being capable of preventing uneven wear of the holding belt. The motion guide device, includes: a track rail; a large number of rolling elements configured to roll on the track rail; a moving block, which has an endless circulation path for the rolling elements, and is configured to freely move along the track rail; and a holding belt having pockets, which are arrayed at predetermined intervals, and are configured to receive the rolling elements, is incorporated into the endless circulation path, and is configured to move in the endless circulation path together with the rolling elements, wherein the holding belt has a pair of end portions opposed to each other through intermediation of a free rolling element in the endless circulation path, and wherein a condition of (X−Y)×Z>(B+C)−A>0 is satisfied, where: A represents a path length of the endless circulation path; B represents a total length of the holding belt; C represents a diameter of the free rolling element; X represents a diameter of each of the pockets; Y represents a diameter of each of the rolling elements; and Z represents the number of the rolling elements arrayed in the holding belt.