Vehicle lifting apparatus

An extendable staircase installed to a vehicle proximate an opening of the vehicle, comprising:

• a plurality of staircase step forming members, each of the staircase step forming members comprising:
• a pair of guide parts arranged at a distance and in parallel with each other,
• a step plate interposed between the pair of guide parts, and
• a protrusion provided in at least one of the guide parts adjacent two of the step forming members at a contacting portion between the guide parts adjacent two of the step forming members,
• the pair of guide parts each having a squarish U-shape cross-section, and arranged such that recesses of the squarish U-shapes of the pair of guide parts face each other,
• the step plate connecting the pair of guide parts so as to transverse the pair of guide parts diagonally and have each end of the step plate extend to a recess of the squarish U-shape of each of the pair of guide parts;
• wherein the guide parts of adjacent two of the step forming members have sizes that are different by thicknesses of one of the guide parts, and
• wherein the staircase step forming members form stairs extending toward a guideway surface by sliding the step forming members with respect to each other.