Device for supporting and moving doors, in particular flap doors, comprising: - a first fixed part intended to be secured to the body of a piece of furniture; - a second part intended to be secured to a door of a piece of furniture; - articulated connection means for jointly connecting said first fixed part to said second movable part so said first fixed part and said second movable part being jointly connected to each other to let said device pass reversibly from: • a retracted configuration wherein said first fixed part and said second part are close to each other, in order to have the door intended to be supported in a closed condition of the internal compartment of the piece of furniture and • an extended configuration wherein said second movable part is more spaced from said first fixed part to have the door intended to be supported in an open condition of the internal compartment of the piece of furniture, said articulated connection means comprise a plurality of articulation pins (6, 6a) extending parallel to each other in a first direction (X-X), said articulated connection means being movable in a moving plane perpendicular to said first direction (X-X), - elastic means kinematically connected via kinematic connection means to a push lever of said articulated connection means to push said push lever with a predetermined elastic load and move said device toward said extended configuration, in which said second movable part is more spaced from said first fixed part wherein: - said elastic means act via said kinematic connection means on a push lever of said articulated connection means in order to push said push lever with a predetermined elastic load and move said device toward said extended configuration only once said second movable part of said device has run a first length of the displacement from said retracted configuration toward said extended configuration of said device and - said articulated connection means are pivoted to rotate around a pin, characterized in that: said elastic means and said kinematic connection means are coplanar and lie in a plane perpendicular to said moving plane of said articulated connection means. - a first fixed part intended to be secured to the body of a piece of furniture; - a second part intended to be secured to a door of a piece of furniture; - articulated connection means for jointly connecting said first fixed part to said second movable part so said first fixed part and said second movable part being jointly connected to each other to let said device pass reversibly from: • a retracted configuration wherein said first fixed part and said second part are close to each other, in order to have the door intended to be supported in a closed condition of the internal compartment of the piece of furniture and • an extended configuration wherein said second movable part is more spaced from said first fixed part to have the door intended to be supported in an open condition of the internal compartment of the piece of furniture, said articulated connection means comprise a plurality of articulation pins (6, 6a) extending parallel to each other in a first direction (X-X), said articulated connection means being movable in a moving plane perpendicular to said first direction (X-X), • a retracted configuration wherein said first fixed part and said second part are close to each other, in order to have the door intended to be supported in a closed condition of the internal compartment of the piece of furniture and • an extended configuration wherein said second movable part is more spaced from said first fixed part to have the door intended to be supported in an open condition of the internal compartment of the piece of furniture, said articulated connection means comprise a plurality of articulation pins (6, 6a) extending parallel to each other in a first direction (X-X), said articulated connection means being movable in a moving plane perpendicular to said first direction (X-X), - elastic means kinematically connected via kinematic connection means to a push lever of said articulated connection means to push said push lever with a predetermined elastic load and move said device toward said extended configuration, in which said second movable part is more spaced from said first fixed part - said elastic means act via said kinematic connection means on a push lever of said articulated connection means in order to push said push lever with a predetermined elastic load and move said device toward said extended configuration only once said second movable part of said device has run a first length of the displacement from said retracted configuration toward said extended configuration of said device and - said articulated connection means are pivoted to rotate around a pin,