To provide a bag with casters which is easily moved even when heavy load is stored while a user strongly puts his (her) weight on a grip whereas the bag is reduced in weight to be easily held up.

The bag with casters includes a bag part 1, casters 6 set up to the bag part 1, and a handle 7 connected to one side of the bag part 1. The handle 7 is structured to connect a plurality of stretchable supports 5 vertically stretchable to one side of the bag part 1 while taking postures parallel to one another at prescribed intervals and fix a grip 4 to the upper ends of the stretchable supports 5. The bag is structured so that the bag part 1 may be supported by the casters 6 in a self-supporting condition. The stretchable supports 5 each includes a hollow pipe, and is composed of a fixation pipe 5B fixed to the bag part 1, and a stretchable pipe 5A inserted into the fixation pipe 5B to be stretchable. The stretchable pipe 5A is structured so that the wall thickness (dy) of a transverse part 5Ay perpendicular to a vertical part 5Ax parallel to both side surfaces 1X of the bag part 1 is thicker than the wall thickness (dx) of the vertical part 5Ax.