To provide a sundial high in accuracy, common in any country on the earth and making the rising and setting positions of the sun and days of the four seasons recognizable like a season calendar in a narrow place by looking from the places of the winter solstice, the summer solstice and each object day of optional days.

A sundial machined into a cylinder 1 of 1m in length and 3cm in diameter is fitted being adjusted to the celestial pole. Supports 3 are provided in positions of 1m on a track right-angled to the cylinder from the place of the vernal- autumnal equinox 4 in the middle of the cylinder, at one-hour intervals so as to divide a circular arc 2 by 15°. The supports 3 are fixed at intervals of 23.45°=0.433775m to an upper winter solstice point 5 and a lower summer solstice point 6 from the vernal-autumnal equinox 4 in the middle of the cylinder. Among these supports, optional observation graduations 7 indexed by 91 days are vertically inscribed in regular order from the middle. The sun appears to move along the circular arc from the inscribed object day so as to become the sundial. This sundial is usable in any place on the earth without needing a large place. Even the rising and setting positions of the sun can be accurately recognized at the time of looking from the places of the winter solstice, summer solstice and an optional day.