A stepless sliding door system, comprising: two sliding doors (10a, 10b) disposed in a closed state thereof on the same plane, along upper and lower parallel rails, at least one of said doors having: • a chassis connected to said sliding door; • two vertical rotatable poles; • two pairs of rail-carts; • two pairs of hand-connectors (36a, 36b), each of the hand-connectors firmly connected in one end thereof to one of said vertical rotatable poles, and pivotally connected in the other end thereof to one of said rail-carts; characterized in that said at least one of said doors further has • two spiral rotation assemblies (72a, 72b), each comprising a vertically shiftable tube in which one of said vertical rotatable poles is disposed, for rotating each of said vertical poles by 90 degrees upon shifting said vertically shiftable tube; and • a transverse rod (60, 54), connecting the vertically shiftable tube of each of said spiral rotation assemblies (72a, 72b), for allowing simultaneous shifting of the vertically shiftable tubes; thereby upon vertically shifting one of said vertically shiftable tubes, simultaneously rotating said vertical poles, resulting in distancing said chassis from said pair of rails, thereby placing said sliding door in parallel to the other sliding door, distantly from the other sliding door, thereby allowing sliding said door in parallel to the other door of said sliding door system such that the doors do not block each other. two sliding doors (10a, 10b) disposed in a closed state thereof on the same plane, along upper and lower parallel rails, at least one of said doors having: • a chassis connected to said sliding door; • two vertical rotatable poles; • two pairs of rail-carts; • two pairs of hand-connectors (36a, 36b), each of the hand-connectors firmly connected in one end thereof to one of said vertical rotatable poles, and pivotally connected in the other end thereof to one of said rail-carts; • a chassis connected to said sliding door; • two vertical rotatable poles; • two pairs of rail-carts; • two pairs of hand-connectors (36a, 36b), each of the hand-connectors firmly connected in one end thereof to one of said vertical rotatable poles, and pivotally connected in the other end thereof to one of said rail-carts; characterized in that said at least one of said doors further has • two spiral rotation assemblies (72a, 72b), each comprising a vertically shiftable tube in which one of said vertical rotatable poles is disposed, for rotating each of said vertical poles by 90 degrees upon shifting said vertically shiftable tube; and • a transverse rod (60, 54), connecting the vertically shiftable tube of each of said spiral rotation assemblies (72a, 72b), for allowing simultaneous shifting of the vertically shiftable tubes; • two spiral rotation assemblies (72a, 72b), each comprising a vertically shiftable tube in which one of said vertical rotatable poles is disposed, for rotating each of said vertical poles by 90 degrees upon shifting said vertically shiftable tube; and • a transverse rod (60, 54), connecting the vertically shiftable tube of each of said spiral rotation assemblies (72a, 72b), for allowing simultaneous shifting of the vertically shiftable tubes; thereby upon vertically shifting one of said vertically shiftable tubes, simultaneously rotating said vertical poles, resulting in distancing said chassis from said pair of rails, thereby placing said sliding door in parallel to the other sliding door, distantly from the other sliding door, thereby allowing sliding said door in parallel to the other door of said sliding door system such that the doors do not block each other.