PURPOSE: To provide a solar beam collecting device in which solar beam can be efficiently collected only through a mere adjustment of an angle of a reflector mirror in respect to a light collector in response to a variation of the solar beam in season.

CONSTITUTION: There is provided a reflector mirror 1 having a parabolic sectional area. A light collector 2 is provided at a focusing point of the reflector mirror 1 or near the focusing point and the light collector is installed substantially in a parallel direction with a reflection plane of the reflector mirror 1 in a longitudinal direction. An angle in a sectional direction where the reflector mirror 1 and the light collector 2 are faced against to each other is adjusted in response to a variation in an incident angle along with a variation of solar beam in season, thereby an energy of the solar beam can be utilized at the maximum value and thus it is possible to provide a solar beam collector device in which the adjustment can be eliminated in response to a variation of incident angle in one day of the solar beam.