Mixer wagon, either self-propelled or intended to be hitched to a tractor vehicle, comprising a mixing tank with a discharge opening, and a discharge device which is associated with the discharge opening and which is able and intended to convey the mixed product leaving the discharge opening and to deposit it on a feeding area located on a lateral side of the said mixer wagon, the said discharge device comprising a belt conveyor arranged transversally relative to the direction of advance of the mixer wagon and extending at least under the discharge opening over its entire width, and the said conveyor being movable transversally with respect to the direction of advance and made up of two portions (6 and 7), in the direction of its longitudinal extension, i.e. a first portion and a second portion, the latter being connected to the first portion by a pivot connection and being movable between several positions inclined with respect to the said first portion, the second portion being in its lower pivoting position coplanar with the first portion and the length (L 1) of the first longitudinal portion of the conveyor being at least equal to the width of the discharge opening of the tank, the length of the first portion being approximately twice the length of the second portion, so that the conveyor has a 1/3-2/3 segmentation, the discharge device comprising, on each lateral side of the second longitudinal portion of the conveyor, a tie rod, pivotally fixed by a first end to the said second portion, mixer wagon comprising either first pivoting movement means (9, 14) for pivoting the second portion and second transverse sliding movement means for transversally sliding the conveyor, the first and second means being mutually separate, the said first pivoting movement means (9, 14) being controlled dependently upon the said second transverse sliding movement means, or first pivoting movement means (9, 14) for pivoting the second portion and second transverse sliding movement means for transversally sliding the conveyor, the first and second means being mutually separate, each of the said first and second movement means comprising its own active element or actuators, mixer wagon wherein: the length of the second longitudinal portion of the conveyor is less than the width of the discharge opening of the tank, the second longitudinal portion extends at least partially under the discharge opening in its rectilinear configuration, i.e. not inclined with respect to the first portion or horizontal, and with no offset, and the two tie rods are of length that is variable by actuation and have second ends that can be moved in translation in a direction parallel to the longitudinal axis of the conveyor. the said discharge device comprising a belt conveyor arranged transversally relative to the direction of advance of the mixer wagon and extending at least under the discharge opening over its entire width, and the said conveyor being movable transversally with respect to the direction of advance and made up of two portions (6 and 7), in the direction of its longitudinal extension, i.e. a first portion and a second portion, the latter being connected to the first portion by a pivot connection and being movable between several positions inclined with respect to the said first portion, the second portion being in its lower pivoting position coplanar with the first portion and the length (L 1) of the first longitudinal portion of the conveyor being at least equal to the width of the discharge opening of the tank, the length of the first portion being approximately twice the length of the second portion, so that the conveyor has a 1/3-2/3 segmentation, the discharge device comprising, on each lateral side of the second longitudinal portion of the conveyor, a tie rod, pivotally fixed by a first end to the said second portion, mixer wagon comprising either first pivoting movement means (9, 14) for pivoting the second portion and second transverse sliding movement means for transversally sliding the conveyor, the first and second means being mutually separate, the said first pivoting movement means (9, 14) being controlled dependently upon the said second transverse sliding movement means, or first pivoting movement means (9, 14) for pivoting the second portion and second transverse sliding movement means for transversally sliding the conveyor, the first and second means being mutually separate, each of the said first and second movement means comprising its own active element or actuators, mixer wagon wherein: the length of the second longitudinal portion of the conveyor is less than the width of the discharge opening of the tank, the second longitudinal portion extends at least partially under the discharge opening in its rectilinear configuration, i.e. not inclined with respect to the first portion or horizontal, and with no offset, and the two tie rods are of length that is variable by actuation and have second ends that can be moved in translation in a direction parallel to the longitudinal axis of the conveyor.