Abstract: A collapsible building which is mounted on the platform of a conveyance has a first elongated unit which is mounted on the platform, and a pair of collapsible elongated units which flank the first unit when the building is fully erected. Each collapsible unit has a base portion including a floor and sidewalls, and a separable roof. The roof is connected to the respective base portion by two pairs of links at the front and rear ends of the respective collapsible unit and each base portion is pivotable relative to the first unit about a horizontal axis extending along the respective side adjacent to the bottom of the first unit. The links compel the roofs to move relative to the respective base portions when the base portions are pivoted by hydraulic motors between upright positions adjacent to the respective sides of the first unit and second positions in which they confine of the first unit.