The condition of a shoe roll is monitored by a device which continuously analyzes the lubricant used in a lubrication system (14) integrated with the shoe roll. The analysis determines the amount of contaminant particles which have entered the lubricant. Particles (19) originating from the belt (13) of a belt roll belonging to the shoe roll (10) are determined in the lubricant. The condition of the belt (13) of a belt roll belonging to the shoe roll (10), and especially the condition of the inner side of the belt (13), can be determined on the basis of the amount of the particles (19).