A centrifuge and a rotor thereof are provided. The centrifuge performs centrifugation in a state where the sample container is swung by rotation and seated in a cutout part of a rotor body. The sample container includes a bucket accommodating a container filled with a sample, and a lid for sealing the bucket and having a rotation shaft. Grooves extending in the longitudinal direction are formed on the outer peripheral surface of the bucket on the bottom side with respect to a seating surface of the bucket. The grooves are arranged at equal intervals in the circumferential direction. Formation of the grooves can prevent increasing the weight of the bucket and realize a highly rigid sample container that can withstand deformation.