To provide a bookrest for use when lying on back and for joining to a stand device, or the like, which makes it possible to hold a book in an opened condition without using a transparent plate or complicated fitting means.

A semicylindrical pedestal arm 1e is provided in a standing condition on a seat plate 1a. A pair of spreading fixing stays 1b is provided on a specified position. Stopper members 1c and 1d for preventing a book from coming loose are provided on a back of the seat plate 1a. An auxiliary spreading fixing stay is slidably fitted to the pedestal arm 1e. The bookrest for use when lying on back 1 having the above construction is joined to the stand device 2.