A transport device for use when mounting interior component modules in an aircraft includes an undercarriage and an interior component module carrier unit. The interior component module carrier unit is supported on the undercarriage and is adapted to be connected to an interior component module, which is preassembled outside of the aircraft, in order to transport the interior component module with the aid of the transport device into a final assembly position in an aircraft fuselage element. At least a part of the interior component module carrier unit is movable relative to the undercarriage such that an interior component module connected to the interior component module carrier unit is movable horizontally and vertically relative to the undercarriage.