Laminate, optical member, and optical apparatus

The present invention provides a laminate of a void-containing layer and a pressure-sensitive adhesive/adhesive layer that achieves both a pressure-sensitive adhesive force or an adhesive force and a reduction of a tendency of a pressure-sensitive adhesive or an adhesive to penetrate into voids. The first laminate of the present invention includes: a void-containing layer (20); and a pressure-sensitive adhesive/adhesive layer (30), wherein the pressure-sensitive adhesive/adhesive layer (30) is directly laminated on one or both sides of the void-containing layer (20), the void-containing layer (20) has a void fraction of 35 vol % or more, and, after a heat/humidification durability test of holding at a temperature of 85° C. and a relative humidity of 85% for 500 hours, a void remaining ratio of the void-containing layer (20) is 50 vol % or more before the heat/humidification durability test.