A collapsible staircase is provided with a set of flat parts, with each of the parts intended to function as steps. Each flat part can be moved between a first position and a second position. All of the flat parts are substantially coplanar when the parts are in the first position, and the parts are disposed above each other and at a distance from each other when the parts are in the second position. A retractable holding handle is also provided and driven together with the flat parts.