PURPOSE: To enable collection of solar heat of high temperatures and high efficiencies by limiting the area of heated parts contacting atmospheric air to prevent the loss of heat radiated to atmospheric air.

CONSTITUTION: The first condensers 1-1 through 1-n are supported by lens supporters 2-1 through 2-n, and focus the solar light beams and transmit the focused beam to the second condensers 4-1 through 4-n. The second condensers 4-1 through 4-n pass the focused beams and transmit the same to a heat collecting conduit pipe 7. Water 8 passing through the heat collecting conduit pipe 7 is successively heated while moving from a solar light beam focus 6-1 to 6-n, which are arranged in series in the number of n. To prevent heat obtained within the heat collecting conduit pipe 7 from escaping to the outside, a heat indulator 9 is fitted on the surface of the outer side of the heat collecting conduit pipe 7 except the surfaces of the second condensers 4-1 through 4-n which derive the solar light beam, thereby to increase the heat collecting effects.