A three dimensional object building device includes a generation unit and a movement controller. The generation unit is configured to generate layer information for each layer of a three-dimensional (3D) object from height information and color information, the height information including information on a three-dimensional position of each pixel of the 3D object, information on a diameter of a dot of build material for the pixel, and information on a gap from an ejection surface of a build unit when the build material for the pixel is to be ejected, the color information indicating a color of each pixel of the 3D object. The movement controller is configured to, when build material for a pixel indicated by the layer information is to be deposited, move the build unit to make a gap correspond to a diameter of a dot for the pixel.