Provided are an improved solid-state image-sensing device for averaging sub-sampled analog signals and a method for driving the same. The solid-state image-sensing device receives a video signal from each pixel column and converts the video signal into a digital signal while a switch for averaging is turned off when the solid-state image-sensing device captures a still image. When the solid-state image-sensing device photographs a moving picture, one of two CDS circuits receives a signal corresponding to an average of video signals of columns having the same color pixel and converts the signal into a digital signal using the switch turned on.