Stereoscopic image display device

A stereoscopic image display device, comprising:

• a display panel including a first display area switchable to two-dimensional display mode or three-dimensional display mode and a second display area;
• and
• a liquid crystal lens unit arranged on a surface side of the display panel and having a liquid crystal layer, distribution of refractive index of the liquid crystal layer being changed by impression of voltage between a first substrate and a second substrate facing the first substrate:
• wherein
• the first substrate includes a first electrode formed in the first and second display areas for controlling alignment of the liquid crystal layer, a second electrode formed in a different layer from the first electrode passing the second display area for supplying a voltage to the first electrode of the first display area, and a third electrode arranged between the second electrode and the liquid crystal layer so that the third electrode has an overlap region with the second electrode in plane in a boundary portion between the first area and the second area, and
• the second substrate includes a fourth electrode formed so as to control the alignment of the liquid crystal layer with the first electrode.