A liquid crystal display device, or more particularly, an active matrix type liquid crystal display device having a pixel electrode formed in a pixel field defined on one of two transparent substrates opposed to each other with a liquid crystal layer between them. The pixel electrode is overlapped a signal line, which is formed in a portion of the one transparent substrate coincident with a black matrix, with a dielectric between them. The width of the overlap is set to a value satisfying a condition that an electric field induced between the signal line and pixel electrode will not invade into the pixel field defined with the black matrix. Owing to the structure, inhomogeneous luminance caused by a source electrode of a thin film transistor can be avoided. Moreover, inhomogeneous luminance caused by a capacitive element can be avoided.