To provide a rainwater storage device by which good quality of the stored water is kept for a relatively long time, the degree of freedom of the setting place is improved, and the operability in maintenance is improved.

This rainwater storage device 1 is provided with a water storage tank 2 for storing rainwater W, a pipe 5 with both ends connected to the water storage tank 2, a filter 6 furnished to the pipe 5 and filtering the water passing through the inside of the pipe 5 and water supply means 4, 9, 10 and 11 for sending the water W stored in the tank 2 from one end of the pipe 5 to the other end.