To provide an extendible book holder capable of setting a plurality of books by rotatably, vertically slidably and fixably mounting a plurality of horizontal arms on a vertical pole, and rotatably, horizontally slidably and fixably mounting horizontal shaft mounting parts fixed to rear stoppers of book holders, on the horizontal arms.

A plurality of parallel arms are rotatably, vertically slidably and fixably mounted around a vertical pole 1. Shaft mounting parts 14 mounted on back surfaces of book holders 13 are rotatably, horizontally slidably and fixably mounted on the parallel arms. A plurality of horizontal arms 21 are fixed to the vertical pole 1 vertically mounted on a desk, through pipe joints 3. The pipe joints 3 respectively consist of two pipe insertion holes and contact face connecting both. Pipe insertion holes 14 of the horizontal shaft mounting parts fixed to the back surfaces of the book holders 13 are respectivel inserted into the horizontal arms 2. Notches are formed inside of the pipe insertion holes 15, and the horizontal arms 2 are fastened and fixed by means of knob screws 17.