We present the analysis of flux variations of Sgr A* at millimeter wavelengths based on the long-term monitoring project spanning over a decade using the Nobeyama Millimeter Array. We investigate basic characteristics of the flux variability using some standard parameterizations of the data. Such basic properties of the flux variations in the mm-regime can provide valuable information not only for its underlying mechanisms in general but also for understanding observed radio/mm flux measurements during an accretion event.