An apparatus and method for visualizing a network condition related to a network security are provided. The apparatus includes a traffic feature extracting unit, a network condition displaying unit, and a traffic abnormal condition determining unit. The traffic feature extracting unit extracts information including source address, source port, destination address, and destination port from network traffics, selects two of the extracted information, and calculates unique dispersion degrees of two unselected information. The network condition displaying unit displays a two-dimensional cube expressed using the calculated unique dispersion degrees for the classified traffics. The traffic abnormal condition determining unit determines whether the traffics are in an abnormal condition or not based on the two-dimensional security cube.