A pushchair accessory (20; 120; 220), including: - a chassis (21; 121; 221) provided with at least one bearing wheel for rolling on the ground (22; 122), and - a device for reversibly connecting to the frame of a pushchair , said device being borne by the chassis, characterized in that the device is suitable for being attached between a left upright and a right upright of the pushchair , which respectively belong to a left rear part (11.1G) and a right rear part (11.1D) of the frame of the pushchair, which are parallel to one another and which have respective faces, opposite one another, in which a first female housing and a second female housing are respectively hollowed, the device including: - a first male element that is movable relative to the chassis between a connection position, in which the first male element is received in a complementary manner in the first female housing when the device is attached between the left and right uprights of the pushchair, and a disconnection position, in which the first male element is outside the first housing, - a second male element that is movable relative to the chassis between a connection position, in which the second male element is received in a complementary manner in the second female housing when the device is attached between the left and right uprights of the pushchair, and a disconnection position, in which the second male element is outside the second housing, and - a mechanism for actuating the first and second male elements, said mechanism being suitable for: - by stress from a single hand of a user, jointly driving the first and second male elements from their connection position to their disconnection position, and - in the absence of stress, automatically returning the first and second male elements from their disconnection position to their connection position. - a chassis (21; 121; 221) provided with at least one bearing wheel for rolling on the ground (22; 122), and - a device for reversibly connecting to the frame of a pushchair , said device being borne by the chassis, - a first male element that is movable relative to the chassis between a connection position, in which the first male element is received in a complementary manner in the first female housing when the device is attached between the left and right uprights of the pushchair, and a disconnection position, in which the first male element is outside the first housing, - a second male element that is movable relative to the chassis between a connection position, in which the second male element is received in a complementary manner in the second female housing when the device is attached between the left and right uprights of the pushchair, and a disconnection position, in which the second male element is outside the second housing, and - a mechanism for actuating the first and second male elements, said mechanism being suitable for: - by stress from a single hand of a user, jointly driving the first and second male elements from their connection position to their disconnection position, and - in the absence of stress, automatically returning the first and second male elements from their disconnection position to their connection position. - by stress from a single hand of a user, jointly driving the first and second male elements from their connection position to their disconnection position, and - in the absence of stress, automatically returning the first and second male elements from their disconnection position to their connection position. <EOS>