To provide a book cover with a light without being bulky and with convenience of portability.

The book cover has a back part 8 covering a back cover 7 of a book 1, and a pair of left and right front decorating parts 9 and 9 respectively continuously provided with both left and right sides of this back part 8 and covering front and back surface covers 11 and 11 of the book 1. A base end 4a of a flexible supporting body 4 with flexibility is fitted on the back part 8. The light 3 for illuminating the book 1 is fitted on the tip of the flexible supporting body 4. Sheet-like secondary batteries 5 with flexibility are respectively built in the left and right front decorating parts 9 and 9 as power supplies for the light 3.