Rotary booth (1; 50) for treating leathers by spraying, comprising: - a load-bearing structure which has at least one loading area in which a leather to be subjected to a spraying treatment is conducted within said load-bearing structure, and a discharge area in which said leather just treated is conducted outside said load-bearing structure; - a conveyor belt (5; 54) mainly housed in said load-bearing structure, adapted to advance along a linear direction said leather received on an upper surface of said conveyor belt (5; 54); - a rotating unit coupled inside said load-bearing structure and provided with spraying means (7; 56) adapted to deposit in sprayed form on said leather, advancing along said linear direction on said conveyor belt (5; 54), at least one fluid painting mixture while said spraying means follow a closed annular trajectory under the rotation of said rotating unit, so that said spraying means (7; 56) take a working condition along two primary circumference arcs (8, 9) belonging to said closed annular trajectory and defined directly above said conveyor belt (5; 54), and a resting condition along two secondary circumference arcs (10, 11), connecting said primary circumference arcs (8, 9) and belonging to said closed annular trajectory, defined externally and laterally to said conveyor belt (5; 54); - suction means (13; 62) operatively connected to said load-bearing structure and adapted to capture by means of an airflow the fumes produced by said spraying treatment inside said load-bearing structure, characterized in that said suction means (13; 62) suck at the spraying area and in the lower part of said load-bearing structure and are distributed according to an arcuate configuration substantially superimposable and equal to an arcuate spatial distribution of said primary circumference arcs (8, 9) belonging to said closed annular trajectory and along which said spraying means (7; 56) take said working condition in which they dispense said fluid painting mixture on said leather advancing on said conveyor belt (5; 54). - a load-bearing structure which has at least one loading area in which a leather to be subjected to a spraying treatment is conducted within said load-bearing structure, and a discharge area in which said leather just treated is conducted outside said load-bearing structure; - a conveyor belt (5; 54) mainly housed in said load-bearing structure, adapted to advance along a linear direction said leather received on an upper surface of said conveyor belt (5; 54); - a rotating unit coupled inside said load-bearing structure and provided with spraying means (7; 56) adapted to deposit in sprayed form on said leather, advancing along said linear direction on said conveyor belt (5; 54), at least one fluid painting mixture while said spraying means follow a closed annular trajectory under the rotation of said rotating unit, so that said spraying means (7; 56) take a working condition along two primary circumference arcs (8, 9) belonging to said closed annular trajectory and defined directly above said conveyor belt (5; 54), and a resting condition along two secondary circumference arcs (10, 11), connecting said primary circumference arcs (8, 9) and belonging to said closed annular trajectory, defined externally and laterally to said conveyor belt (5; 54); - suction means (13; 62) operatively connected to said load-bearing structure and adapted to capture by means of an airflow the fumes produced by said spraying treatment inside said load-bearing structure,