An IPS system liquid crystal display device is provided to prevent reliability for a seal portion from lowering, which is caused by the fact that an overcoat film at a portion where an alignment film is not present is deteriorated by ultraviolet light during optical alignment process. An alignment film 113 subjected to optical alignment is formed above each surface of a TFT substrate 100 and of a counter substrate 200, the alignment film 113 on the side of the TFT substrate 100 is not formed in the seal portion, and a sealant 150 is bonded to an inorganic insulating film 109. On the side of the counter substrate 200, the alignment film 113 is formed on an overcoat film 203 and the sealant 150 is bonded to the alignment film 113. Since the ultraviolet light is not radiated directly to the overcoat film 203 when optical alignment is performed on the alignment film 113, the overcoat film 203 can be prevented from deterioration and, accordingly, intrusion of moisture from the deteriorated portion of the overcoat film can be prevented.