Abstract: A winding apparatus for winding a paper web, comprising a reel spool onto which the web is wound to form a paper roll, a support member forming a nip with the paper roll, and an actuator mounted at the support member or reel spool to control the distance therebetween. According to the invention the apparatus has a measuring and controlling equipment comprising a light-emitting member to illuminate the paper roll by light providing a line on the cylindrical surface of the paper roll, a receptive system arranged to depict the line, and a control unit connected to the receptive system and arranged to analyze the depicted line in order to calculate the distance between the paper roll and the support member and send a position-correcting signal to the actuator when the distance calculated deviates from a predetermined distance. The invention also relates to such a measuring and controlling equipment and a method for controlling the distance between the paper roll and the support member.