To provide a medicine automatic dispenser wherein a cassette housing space is sufficiently secured to house a lot of medicine and in particular, the installation construction is easily performed.

The medicine automatic dispenser is characterized in that a cassette shelf 12 for housing a plurality of cassettes is disposed in the cassette housing space 10A provided on the front surface side of a medicine mounting unit 10, a medicine take-out mechanism part is disposed in a medicine take-out space 10B provided on the rear surface side of the medicine mounting unit 10, the medicine mounting unit 10 is disposed on one side surface of a medicine injecting unit 20, and a tray housing unit 30 is disposed on the other side surface of the medicine injecting in particular unit 20.