a light source apparatus comprises reflection mirrors , first and second lamp holding sections , wherein the reflection mirrors are provided between the first and second lamp holding section , a reflection mirror support plate to which reflection mirrors are attached , a first lamp holding section support plate to which the first lamp holding section is attached , a second lamp holding section support plate to which the second lamp holding section is attached , a first fixing member which fixes the reflection mirror support plate and the first lamp holding section support plate to each other , a second fixing member which fixes the reflection mirror support plate and the second lamp holding section support plate to each other .