The invention relates to a labelling machine for applying labels onto articles intended to contain a pourable product and comprising a conveyor and a transfer element. The labelling machine also comprises first detection means, arranged peripherally to the transfer element in a position downstream of an application station and upstream of a receiving station, relatively to an advancement direction. The first detection means is configured to detect the single labels still retained in use and to generate a presence signal correlated with the presence of the labels, by the lateral surface downstream of the application station. The labelling machine comprises second detection means arranged in a position downstream of the receiving station and upstream of the application station, relatively to the advancement direction, and configured to detect a positioning of each label onto the lateral surface and to generate a positioning signal correlated with the positioning of each label.