To provide an IPS (In-Plane Switching) mode liquid crystal display device which is excellent in display quality.

In the IPS mode liquid crystal display device of a normally black mode wherein a first polarizing plate, a liquid crystal cell, a negative and nearly monoaxial optical film having an optical axis in its plane, a positive and nearly monoaxial optical film having an optical axis in its thickness direction, a second polarizing plate are laminated in this order, an absorption axis of the first polarizing plate and a delay phase axis in the plane of the liquid crystal cell in a black state form an angle of nearly 90°, the delay phase axis in the plane of the liquid crystal cell and a delay phase axis of the negative and nearly monoaxial optical film form an angle of nearly 90° and the delay phase axis of the negative and nearly monoaxial optical film and an absorption axis of the second polarizing plate form an angle of nearly 90°.