Disclosed is a portable device holder for vehicle CD-slot mounting, and more particularly to a portable device holder for vehicle CD-slot mounting, in which a facing distance between a movable piece and a stationary piece to be inserted in a CD slot of a vehicle becomes shorter when external forces act thereon, and the facing distance between the movable piece and the stationary piece to be inserted in the CD slot of the vehicle becomes longer when no external forces act thereon, thereby being easily inserted in and mounted to the CD slot of the vehicle and keeping a stable and secured mounting state.