A fixed angle hybrid centrifuge rotor includes an outer portion of composite material reinforced with fiber at least along a peripheral direction, an inner portion having stiffness less than ⅕ of stiffness of the outer portion and provided with a plurality of slots receiving specimens, and a reinforcer of composite material mounted into the slots of the inner portion, the reinforcer fabricated from material having higher stiffness than that of the inner portion and reinforced with fiber along at least peripheral direction of the slot. The reinforcer penetrates the inner portion and at least a part of the reinforcer downwardly protrudes from the inner portion. The rotor can rotate at a high speed and provides improved safety.