A small-sized, inexpensive automatic sample exchange device for use with an NMR spectrometer. The exchange device has a mechanism acting to convey sample tubes and also to grip them. The exchange device includes a disk plate located just above a sample inlet hole formed in the spectrometer. The disk plate has a fringe portion provided with a recess. The sample tubes are inserted into a given number of sleeves, which are mounted to a turntable and to the disk plate. An ultrasonic motor rotates the turntable, the disk plate, and the sleeves integrally. When the sleeves register with the recess in the disk plate, the fringe portion of the disk plate does not protrude into holes formed in the sleeves. When the sleeves do not register with the recess, the fringe portion protrude into the holes in the sleeves, thus gripping the sample tubes.