Reminder device for indication of time-related information for a pen-shaped medical delivery device, the reminder device comprising:a housing part comprising a guiding device,an adjusting element which is movably disposed on the guiding device for selecting of a position of the adjusting element for indication of a time information,an indication device disposed along the guiding device and having an outer surface with sequential time indicia disposed thereon, wherein the indication device provides a time indication which corresponds to the position of the adjusting element, so that a user can mark a time information on the pen-shaped medical delivery device.