Abstract: A truck (20) journaling a wheel (W) is turnably supported leftward and rightward from a neutral position and, at the same time, a support (1) for returnably urging the truck (20) to the neutral position is provided. The support (1) comprises a weighting table (2) fixed to a deck (D) and a support table which is pivotally connected to this weighting table (2) and detachably and attachably fixes the truck. A link piece (7) is pivotally connected between the weighting table 2 and the support table (10) and, when the support table (20) is turned leftward and rightward from the neutral position, the support table (10) is allowed to return to the neutral position due to a repulsive force of a coil spring (S).