A bicycle carrier includes a main shaft having a spacer, two upper stands mounted on the main shaft and abutting the spacer, two carrying racks mounted on the main shaft and respectively abutting the upper stands, two lower stands mounted on the main shaft and respectively abutting the carrying racks, and two end caps mounted on the main shaft and respectively abutting the lower stands. The spacer has two ends each provided with a first ratchet ring. Each of the upper stands has a first mounting ring which has two ends each provided with a second ratchet ring. Each of the carrying racks has a second mounting ring which has two ends each provided with a third ratchet ring. Each of the lower stands has a third mounting ring which has two ends each provided with a fourth ratchet ring.