A testing method for an array substrate is disclosed which includes a first measuring step of operating a line electrode driver circuit 15 and a row electrode driver circuit 16 like in a normal display mode while implementing writing in/reading out of a test video signal to and from supplemental capacitors 13, and a second measuring step of implementing writing in/reading out of the test video signals to and from a video bus 163 while rendering TFTs 11 of a pixel section 18 and analog switches 162 of the row electrode driver circuit 16 to be held turned off. Obtaining a difference between a measured result of the first measuring step and a measured result of the second measuring step allows only a pixel component and a row electrode component with no driver component to be derived, whereupon discrimination is implemented for the presence of or the absence of electric defects in the pixel section.