A stacker device (1; 101; 201) for stacking flats on edge, which device includes: • a stacking support (2; 102; 202) that extends along a certain stacking axis for storing flats on edge and in a stack, which flats are inserted successively onto said stacking support (2; 102; 202); • a stacking actuator (4; 104; 204) designed for guiding each flat to be stacked along an insertion axis transverse to the stacking axis, for inserting it at a first end of said stack of flats, and for pushing said first end of the stack while the flat is being inserted along the stacking axis; and • a retaining element that is mounted to move along the stacking axis and that is designed to retain the stack of flats at a second end of the stack that is opposite from said first end, while pushing the stack of flats towards the stacking actuator (4; 104; 204) as the stack of flats is being formed; wherein said stacking support (2; 102; 202) is mounted to move along the stacking axis in both directions, and wherein said stacker device (1; 101; 201) includes impulse means (9; 109; 209) synchronized with the stacking actuator (4; 104; 204) so as to move said stacking support (2; 102; 202) by direct contact in the direction along said stacking axis that goes away from the stacking actuator (4; 104; 209), said impulse means (9; 109; 209) including return means (12; 112; 2012) for bringing back the stacking support towards the stacking actuator (4; 104; 209) along the stacking axis, said stacker device being characterized in that the stacking actuator (4; 104; 204) is a mechanical actuator mounted to rotate about a main axis embodied by a stationary pin in the stacker device (1; 101; 201), and in that said impulse means (9; 109; 209) comprise a mechanical thrust actuator (10; 110; 210) that is mounted to rotate about said main axis and that drives said stacking support (2; 102; 202) by mechanical contact so as to move it in translation along the stacking axis. • a stacking support (2; 102; 202) that extends along a certain stacking axis for storing flats on edge and in a stack, which flats are inserted successively onto said stacking support (2; 102; 202); • a stacking actuator (4; 104; 204) designed for guiding each flat to be stacked along an insertion axis transverse to the stacking axis, for inserting it at a first end of said stack of flats, and for pushing said first end of the stack while the flat is being inserted along the stacking axis; and • a retaining element that is mounted to move along the stacking axis and that is designed to retain the stack of flats at a second end of the stack that is opposite from said first end, while pushing the stack of flats towards the stacking actuator (4; 104; 204) as the stack of flats is being formed; wherein said stacking support (2; 102; 202) is mounted to move along the stacking axis in both directions, and wherein said stacker device (1; 101; 201) includes impulse means (9; 109; 209) synchronized with the stacking actuator (4; 104; 204) so as to move said stacking support (2; 102; 202) by direct contact in the direction along said stacking axis that goes away from the stacking actuator (4; 104; 209), said impulse means (9; 109; 209) including return means (12; 112; 2012) for bringing back the stacking support towards the stacking actuator (4; 104; 209) along the stacking axis, said stacker device being characterized in that the stacking actuator (4; 104; 204) is a mechanical actuator mounted to rotate about a main axis embodied by a stationary pin in the stacker device (1; 101; 201), and in that said impulse means (9; 109; 209) comprise a mechanical thrust actuator (10; 110; 210) that is mounted to rotate about said main axis and that drives said stacking support (2; 102; 202) by mechanical contact so as to move it in translation along the stacking axis.