The origin of the fog in the Namib Desert was generally considered the westerly advection fog over the Benguela cold current. When the author went to the Namib Desert in dry seasons in 2003 and 2004, the fog in the early morning, however, moved easterly from the inland to the Atlantic Ocean. It was the opposite direction of so called the sea fog. In addition to that, the fog in the Namib Desert showed the diurnal change: the fog arises in the early morning and disappeared before noon. The fog was usually driven easterly to the Atlantic Ocean. Through the climatic observation, the following were found for consideration of the origin of the fog on early August, 2004: it is not advection fog but that it is radiation fog. In the daytime, the air which is comparatively moist because of sea breeze moved to the inland, and it is solidifi ed by radiative cooling in the night. Thus, the water vapor runs the fog and it is blown by the land wind to the westward. Keywords: Radiation fog, Advection fog, Namib Desert, Diurnal change, Observation.