Abstract: A movable workbench 6 has a work board 7, second casters 8 attached on one side of the back of the work board, and first casters 9 attached on the other side thereof. The first casters 9 can rotate freely around an axis of rotation 91 perpendicular to the back of the work board 71, and have rollers 92 and 93 which can rotate freely around axes of rotation 92a and 93a respectively which are inclined symmetrically with respect to the axis 91. The rollers 92 and 93 also have plates to prevent running off 94 and 95 respectively. Because the pair of rollers 92 and 93 are put on a cylindrical rail 35 and roll along the rail, the movable workbench 6 can be moved along the rail by manpower. Since each of the casters can rotate freely, the casters can be moved along an arc-like line. In addition, the plates 94 and 95 prevent the workbench 6 from running off the rail even if the workbench is inclined.