A device for sanitizing or cleaning the handrail of a mobile conveyor for a person, for example an escalator or moving walkway, the device comprising: - A tank for containing a sanitizing or cleaning substance, for example a sanitizing or cleaning liquid; - Means for connecting said device to the said mobile conveyor; - A dispensing assembly (8, 10, 23) of said sanitizing or cleaning substance; - And in which a feeding path is included for feeding, by gravity, said sanitizing or cleaning substance from the tank to the dispensing assembly (8, 10, 23); - Wherein said dispensing assembly (8, 10, 23) comprises at least one dispenser roller and a collecting tray and with said dispenser roller rotatably mounted at least partially inside said collecting tray where, in utilization, said sanitizing or cleaning substance is conveyed; - Wherein said rotating dispenser roller is rotatably mounted idlingly; - Characterized in that: - Said tank is connected to the collecting tray by means of an arm so that, in utilization, the tank is positioned above the said collecting tray thereby feeding it by gravity; - Said means for connecting the sanitizing device to said mobile conveyor comprise quick coupling means, said quick coupling means being provided in correspondence with the tank, in such a way as to allow, in utilization, fixing of the tank to a part of the said mobile conveyor with the tank placed above the collecting tray, thereby feeding the collecting tray by gravity and with said idle rotating dispensing roller placed under said tank in contact with the handrail of the mobile conveyor in such a way that it is dragged into rotation by the motion of said handrail. - A tank for containing a sanitizing or cleaning substance, for example a sanitizing or cleaning liquid; - Means for connecting said device to the said mobile conveyor; - A dispensing assembly (8, 10, 23) of said sanitizing or cleaning substance; - And in which a feeding path is included for feeding, by gravity, said sanitizing or cleaning substance from the tank to the dispensing assembly (8, 10, 23); - Wherein said dispensing assembly (8, 10, 23) comprises at least one dispenser roller and a collecting tray and with said dispenser roller rotatably mounted at least partially inside said collecting tray where, in utilization, said sanitizing or cleaning substance is conveyed; - Wherein said rotating dispenser roller is rotatably mounted idlingly; - Characterized in that: - Said tank is connected to the collecting tray by means of an arm so that, in utilization, the tank is positioned above the said collecting tray thereby feeding it by gravity; - Said means for connecting the sanitizing device to said mobile conveyor comprise quick coupling means, said quick coupling means being provided in correspondence with the tank, in such a way as to allow, in utilization, fixing of the tank to a part of the said mobile conveyor with the tank placed above the collecting tray, thereby feeding the collecting tray by gravity and with said idle rotating dispensing roller placed under said tank in contact with the handrail of the mobile conveyor in such a way that it is dragged into rotation by the motion of said handrail.