To provide a portable recorder mounting device on a music stand solving problems such that, when a portable recorder is put on a conventional auxiliary shelf, it is easily fallen due to the almost horizontal face of the shelf, and the auxiliary shelf itself is fitted to a lateral plate portion of a music rest of the music stand and easily fallen.

This mounting device 2 for mounting the portable recorder 4 on the music rest 3 of the music stand 1, which is formed of angle members comprising vertical plate portions 3a and lateral plate portions 3b, is constituted of a U cross sectional locking part 5 fitted to the vertical plate portion 3a from the upper part, a U cross sectional retaining part 6 fitting the portable recorder 4 from above and retaining it, and a connecting part 7 integrally connecting the locking part 5 to the retaining part 6.