Akira, you obviously have better eyesight than I. 
All rainbows are double. The primary rainbow is at 42 degrees from the anti-solar point, and the outer or secondary rainbow is at 51 degrees. The secondary rainbow is always broader and less bright than the primary rainbow, so it is often hard to see. Note that the colours are reversed - in the inner rainbow red is on the outside and on the outer rainbow it is on the inside.
There are also third and fourth order rainbows, but they are seen in the other direction, towards the sun, and are centred on the sun so they are hard to see and harder to photograph - the first photograph of a third order rainbow was made only in 2011!
Two other phenomenon Akira's picture illustrates is that the the sky within the primary rainbow is brighter than the rest of the sky, and that the sky between the primary and secondary rainbows is darker than the rest of the sky (this is called "Alexander's dark band").
