To provide a semiconductor device member that is superior in heat resistance, light resistance, film-formation capability and adhesion, and is capable of sealing a semiconductor device and holding a phosphor without causing cracks, peelings and colorings even after used for a long period of time, the weight loss at the time of heating, measured by a predetermined weight-loss at-the-time-of-heating measurement method, is 50 weight % or lower and the ratio of peeling, measured by a predetermined adhesion evaluation method, is 30% or lower, in the semiconductor device member.