We study a 360-degree magnetic domain wall (360DW) in a Co submicron structure consisting of a ring and a wire shape. The 360DW formation and configuration are investigated by using a magnetic force microscopy image (MFM) technique, in which the 360DW configuration can be controlled by using the direction of the magnetic field. Anisotropic magnetoresistance measurements are applied to understand the effects of the formation and the configuration of the 360DW on the resistance change in the switching process in terms of the magnetic applied field, and the results are consistent with the MFM measurements and the micromagnetic simulations.