A support assembly that supports a device main body to be able to rotate includes a base member supported on an installation surface, a support unit having a predetermined curvature, coupled with the device main body on one side thereof, and reciprocating according to tilting of the device main body between an upright position and a tablet position, a guide rail coupled with the base member on a first side thereof and supported by the support unit on a second side thereof, to guide the reciprocation of the support unit, and an elastic unit connected to the support unit and providing an elastic force to maintain a tilting position of the device main body. A computer device may include the support assembly. The support assembly may support a computer device main body having a display when the computer device main body tilts between the upright position and the tablet position.