To provide a heavy load mounting and traveling device wherein traveling is not disturbed even when there is a small difference on a traveling floor surface.

A housing space 4 surrounded by right and left frame members and front and rear frame members 3 is divided into upper and lower stages by a guide member 5. The upper and lower stages of the space 4 are continued with each other in front and rear parts, and the annularly continuous housing space is formed as the whole, and a plurality of spherical bodies 6 are housed so as to be rolled. A lower end of the front and rear frame members 3 is positioned higher than a lower end of the right and left frame members. Guide protrusion pieces 7 are continuously provided protrudingly on the lower end of the right and left frame members so that a width between foremost ends is smaller than a diameter of the spherical body. The lower end of the right and left frame members is gradually raised as going to front and rear ends.