To provide a slat opening/closing device generating electric energy by receiving indoor light.

The slat opening/closing device includes a base 2 arranged on a structure 1 having a translucent window 10 allowing the light to penetrate therethrough, and a slat group 3 comprising a plurality of slats 4 arranged side by side in one direction and closing the translucent window 10 of the structure 1. At least one of the slats 4 serves as a rotary slat 4R rotatable with respect to the base 2. The slat opening/closing device further includes an operation part 7 rotating the rotary slat 4R. The rotary slat 4R includes a solar battery 6 generating the electric energy when receiving the light. The rotary slat 4R is arranged at the position where the solar battery 6 is oriented to the side of the interior 52 so that the solar battery 6 can receive the indoor light when the slat group 3 covers the translucent window 10.