To provide a glass substrate unit which can suppress the occurrence of crosstalk without increasing its manufacturing cost, and is used for a stereoscopic image display device.

A glass substrate unit 110 used for the stereoscopic image display device includes a glass substrate 111 having a first surface 111a and a second surface 111b. The first surface 111a faces an image display unit of the stereoscopic image display device, and the second surface 111b faces a user. A parallax barrier 30 is formed on the second surface 111b and has light transmitting sections 31 and light shielding sections 32. Recesses and protrusions 115 having light scattering characteristics are formed on the first surface 111a, and a color filter 112 is formed on the recesses and protrusions 115.