A prompting apparatus for prompting to fasten a seatbelt for a vehicle, which includes: a detector which detects whether the seatbelt is fastened or unfastened; a warning device which warns that the seatbelt is unfastened and is capable of changing a warning level; and a controller which controls an actuation of the warning device. The controller intensifies a warning level of the warning device in steps in conjunction with a predetermined condition if the vehicle is in motion when the detector has detected that the seatbelt is unfastened.