To provide a calendar describing information on distance of the moon and attention-requiring days due to the distance of the moon.

A calendar 80 integrates phases of the moon and distance of the moon, and shows the distance of the moon by display sizes of the phases of the moon. By this, users can complexly and intuitively figure out lateral movements and vertical movements of the moon. As the calendar gives warning labels 40a, 40b to an intermediate day between the farthest day and the nearest day with statistically high probability of occurring disasters, big accidents, climate change, and poor physical conditions, the users can visually figure out attention-requiring days due to the distance of the moon.