Retractable platform comprising a box-like container in which is housed, in rest position (R), an extractable step to be arranged in operating position (W), said retractable platform being provided for equipping lateral or rear access doors (P) of commercial, camping or multi-purpose vehicles, so as to constitute an intermediate step between the ground (T) and the threshold (S) of one of said access doors (P), said retractable platform being provided with a movement device characterized in that it provides: - an electric gearmotor assembly , arranged inside said box-like container , intended to rotate, in both directions, a gearwheel with which a coiled flexible cable of suitable length is engaged in gearing, arranged tangentially to said gearwheel, so that the rotation of the latter imparts straight forwards or backwards translations thereto; - a straight guide , made integral with said box-like container , with orientation parallel to the direction (X) of entry and exit of said extractable step , and having a length at least equal to the useful extraction and return stroke provided for the same extractable step , with said straight guide in a form suitable for slidably housing said coiled flexible cable , retaining it therein and keeping it straight; - a bracket , fixed to the front end of said coiled flexible cable , so as to be external to said straight guide , with said bracket intended to be made integral with said extractable step , so as to imprint thereon, as a result of the translations of said coiled flexible cable , the respective aforementioned useful extraction and return strokes; - a shaped tubular sheath , rearwardly associated with said electric gearmotor assembly , intended to receive and house the rear portion of said coiled flexible cable , as a result of said useful return stroke of the extractable step in said box-like container . - an electric gearmotor assembly , arranged inside said box-like container , intended to rotate, in both directions, a gearwheel with which a coiled flexible cable of suitable length is engaged in gearing, arranged tangentially to said gearwheel, so that the rotation of the latter imparts straight forwards or backwards translations thereto; - a straight guide , made integral with said box-like container , with orientation parallel to the direction (X) of entry and exit of said extractable step , and having a length at least equal to the useful extraction and return stroke provided for the same extractable step , with said straight guide in a form suitable for slidably housing said coiled flexible cable , retaining it therein and keeping it straight; - a bracket , fixed to the front end of said coiled flexible cable , so as to be external to said straight guide , with said bracket intended to be made integral with said extractable step , so as to imprint thereon, as a result of the translations of said coiled flexible cable , the respective aforementioned useful extraction and return strokes; - a shaped tubular sheath , rearwardly associated with said electric gearmotor assembly , intended to receive and house the rear portion of said coiled flexible cable , as a result of said useful return stroke of the extractable step in said box-like container . <EOS>