NOVELTY - The solar battery unit (1) has main portion case (3) that accommodates secondary battery (15) which supports a solar panel (2) and electrically stores electric power from the solar panel. An outer peripheral wall (5) is formed so that outer periphery of the main portion case is covered. Space portion (6) is provided between a bottom face (2a) of the solar panel and an upper surface (3a) of the main portion case. The outer peripheral wall is provided with water/air flow hole (7) to perform the ventilation to the space portion.    USE - Solar battery unit used for driving power supply of object detection apparatus (claimed) used for object detection by security sensor installed in outdoor.    ADVANTAGE - The water/air flow hole is provided in the outer peripheral wall while heightening that heat insulation effect by ventilating the space portion by the water/air flow hole which insulates the main portion case by the space portion provided between the solar panel and the main portion case which accommodates a secondary battery. The outer peripheral wall suppresses the raise of the temperature inside the main portion case by light-shielding of main portion case by the wall surface. The wall surface of the outer peripheral wall has an effect which improves the waterproofness and insect-proof property with respect to the inside of main portion case. The temperature rise in the main portion case which accommodates the secondary battery which electrically stores the electric power from solar panel is suppressed, and the lifetime performance of the secondary battery is improved. Since the lifetime performance of the secondary battery is high, the solar battery unit is fully applicable to the driving power supply of object detection apparatus. The solar battery unit is simple in structure and having low-cost.    DESCRIPTION OF DRAWING(S) - The drawing shows a side view of the solar battery unit. (Drawing includes non-English language text)    Solar battery unit (1)    Solar panel (2)    Bottom face of solar panel (2a)    Main portion case (3)    Upper surface of main portion case (3a)    Outer peripheral wall (5)    Space portion (6)    Water/air flow hole (7)    Secondary battery (15)