This light source apparatus includes a wheel, a motor, a rotation member, and a contact member. The wheel includes a light emitter that is excited by excitation light and emits visible light, and a base that includes a first surface and a second surface opposite thereto, supports the light emitter on either one of the first and second surfaces, and has a first linear expansion coefficient. The motor generates rotational force for rotating the base. The rotation member is connected to the first surface of the base, rotates integrally with the base due to the rotational force of the motor, and has a second linear expansion coefficient different from the first linear expansion coefficient. The contact member is connected to the second surface of the base and has a third linear expansion coefficient whose magnitude relationship to the first linear expansion coefficient is equal to a magnitude relationship of the second linear expansion coefficient to the first linear expansion coefficient.