To provide a solar water heater capable of collecting a great amount of solar incident beams into a heat collecting plate and a heat exchanger, and capable of elevating heat-collectingly a surface temperature of the heat collecting plate to enhance a quantity of heat.

The temperature of the heat collecting plate is heightened and a heat collecting efficiency is enhanced when used in a cold meteorological condition, by a light-collecting heat-collection system for collecting the solar incident beams and for collecting the incident beams along the heat exchanger assembled in a planar type heat collector, different from a conventional heat collector, with integration with a transparent reinforced glass plate of light collection structure.