A handheld centrifuge includes an inertia body having an axle and a pair of inertia wheels coupled to the axle. The inertia wheels are coupled to the axle in substantially perpendicular direction to the axle, and spaced apart from each other. A string is connected to the axle. At least one closed vessel is detachably installed on an outer face of the inertia wheel to contain a substance to be centrifuged. The closed vessel is installed in substantially radial direction of the inertia wheel.