A medical-use light-source apparatus includes a light source lamp, a connector to which a body cavity endoscope and an ophthalmic observation apparatus can be selectively connected, a determiner which determines whether the body cavity endoscope or the ophthalmic observation apparatus is currently connected to the connector, and a lamp controller which sets a value of a maximum light amount of the illumination light to a first threshold value when the determiner determines that the body cavity endoscope is currently connected to the connector, and sets a value of a maximum light amount of the illumination light to a second threshold value that is smaller than the first threshold value when the determiner determines that the ophthalmic observation apparatus is currently connected to the connector.