A holding device configured to hold a ladder against a surface, the holding device comprising: - a structure defining a bearing plane intended to be disposed facing the surface; - at least one mounting element allowing the mounting of the structure on the surface; - a first holding element and a second holding element configured to cooperate with the ladder so as to hold the ladder against the surface, the first and second elements holding elements (7, 9) being mounted on the structure and being disposed facing each other along a clamping direction, the first and second holding elements (7, 9) being configured to be moved relative to each other along the clamping direction so as to be moved apart or tightened, thus forming a jaw that allows inserting the ladder between the first and second holding elements (7, 9), wherein each of the first and second holding elements (7, 9) is able to pivot so as to adapt to the inclination of the ladder, wherein the structure comprises a first portion and a second portion, the first and second portions (11, 13) being connected to each other via a sliding connection, the first holding element being mounted on the first portion and the second holding element being mounted on the second portion, wherein the first and second holding elements (7, 9) have a U shape and each comprise a receiving space (41, 42) intended to receive an upright (3a, 3b) of the ladder, characterized in that the receiving space (41, 42) is delimited by an outer abutment (43, 45) extending substantially parallel to the bearing plane, intended to hold the ladder against the surface, an inner abutment (47, 49), disposed facing the outer abutment (43, 45), and a clamping portion (51, 53) disposed between the inner abutment (47, 49) and the outer abutment (43, 45). - a structure defining a bearing plane intended to be disposed facing the surface; - at least one mounting element allowing the mounting of the structure on the surface; - a first holding element and a second holding element configured to cooperate with the ladder so as to hold the ladder against the surface, the first and second elements holding elements (7, 9) being mounted on the structure and being disposed facing each other along a clamping direction, the first and second holding elements (7, 9) being configured to be moved relative to each other along the clamping direction so as to be moved apart or tightened, thus forming a jaw that allows inserting the ladder between the first and second holding elements (7, 9), wherein each of the first and second holding elements (7, 9) is able to pivot so as to adapt to the inclination of the ladder, wherein the structure comprises a first portion and a second portion, the first and second portions (11, 13) being connected to each other via a sliding connection, the first holding element being mounted on the first portion and the second holding element being mounted on the second portion, wherein the first and second holding elements (7, 9) have a U shape and each comprise a receiving space (41, 42) intended to receive an upright (3a, 3b) of the ladder, characterized in that the receiving space (41, 42) is delimited by an outer abutment (43, 45) extending substantially parallel to the bearing plane, intended to hold the ladder against the surface, an inner abutment (47, 49), disposed facing the outer abutment (43, 45), and a clamping portion (51, 53) disposed between the inner abutment (47, 49) and the outer abutment (43, 45). wherein each of the first and second holding elements (7, 9) is able to pivot so as to adapt to the inclination of the ladder, wherein the structure comprises a first portion and a second portion, the first and second portions (11, 13) being connected to each other via a sliding connection, the first holding element being mounted on the first portion and the second holding element being mounted on the second portion, wherein the first and second holding elements (7, 9) have a U shape and each comprise a receiving space (41, 42) intended to receive an upright (3a, 3b) of the ladder, characterized in that the receiving space (41, 42) is delimited by an outer abutment (43, 45) extending substantially parallel to the bearing plane, intended to hold the ladder against the surface, an inner abutment (47, 49), disposed facing the outer abutment (43, 45), and a clamping portion (51, 53) disposed between the inner abutment (47, 49) and the outer abutment (43, 45).