According to one embodiment, a liquid crystal display device comprises first and second substrates and a liquid crystal layer. The first substrate includes a base member, a sensor between the base member and the liquid crystal layer, a collimation layer between the sensor and the liquid crystal layer, an insulating layer between the sensor and the collimation layer, an insulating layer, and a light shielding layer between the sensor and the base member. The sensor is configured to output a signal corresponding to light incident from a liquid crystal layer side. The light shielding layer overlaps with an outer peripheral part of the first collimation layer.