To enable a user to enjoy making a calendar which is usable over a long period of time and is optimum for saving resources.

The simple calendar 1 consists of a box-shaped case body 2, a cap 3 which is openably and closably disposed at this body, plural calendar displays 4 which displays the date in Arabic numerals by segmenting these numerals to five columns on the respective surfaces of a prism, a name-of-the-era-display 5 displaying the name-of-the-era in Arabic numerals a twelve-signs-of-the zodiac display 7 which displays the twelve signs of the zodiac and a mouth display 6 which displays the mouth in Arabic numerals. This box shaped case body 2 has a calendar display housing part 2b, a name-of-the-era display housing part 2c, a twelve-signs-of-the zodiac display housing part 2d and a month display housing part 2e. The cap 3 has a calendar display window 3a, a name-of-the-era display window 3b, twelve-signs-of-the zodiac display window 3c, a month display window 3d and a day-of-the-week display window 3e. The display of the month of the prescribed name of the era is made possible by the name-of-the-era display and the month display. The display of the date of the specific month of the prescribed name of the era is made possible in correspondence to the day-of-the-week display part 3e by combining the plural calendar displays. The display of the twelve signs of the zodiac is made possible by the twelve-signs-of-the zodiac display.