Provided is a rotating assembly. The rotating assembly is for forming a microstructure, and comprises: a rotating body rotatable about a rotary shaft; a first support member installed on the rotating body so as to be spaced apart from the rotational shaft and having a predetermined viscous composition disposed on an outer surface thereof; and a fluid communicating portion for communicating the inside and the outside of the rotating body, wherein when the rotating body rotates, the viscous composition is pulled in a radially outward direction of the rotary shaft, and the pulled viscous composition is cured through the fluid communicating portion, thereby forming a microstructure.