To provide a calendar which makes it possible to get individual astrological information on twelve constellations of astrology, although it is an ordinary calendar that is not specially ordered as to each date of birth or each constellation, but can be purchased by an unspecified large number of persons, and which can also indicate biorhythms of persons of four blood types in total.

The calendar represents a monthly indication having a calendar indication part which keeps the indication of days of the week arranged laterally in the top part and days arranged laterally, being turned back by one week, downward in repetition. The calendar indication part is so constituted that each day is indicated in a square formed by frame lines, and means for indicating the astrological twelve constellations and prescribed means for indicating items of good fortunes that the twelve constellations have are shown respectively in the squares.