Abstract: A light source apparatus is provided. The light source apparatus comprises an electric-conductive terminal, a control circuit, a first light source device, and a second light source device. The electric-conductive terminal defines a receiving space. The control circuit is disposed within the receiving space of the electric-conductive terminal and is electrically connected to the electric-conductive terminal. The first light source device and the second light source device are both electrically connected to the control circuit. When the control circuit detects a switching signal, the control circuit enables the first light source device to change from a first brightness to a second brightness and enables the second light source device to change from a third brightness to a fourth brightness.