An illumination apparatus includes a housing, a light source module, and a heat dissipation structure including heat sink fins, a shutter structure, and a variable element. The housing provides a bottom and an outlet disposed at one side of the bottom. The heat sink fins are disposed in the housing and thermal conductivity connected with the light source module. The shutter structure is disposed on the outlet and includes guiding plates, a connecting rod, and an operating element. Each of guiding plates is connected to the connecting rod. The operating element is disposed at one end of the connecting rod and provides an operating force for the connecting rod. The variable element is near the heat sink fins and connected with the connecting rod, the variable element is deformed to exert a force on the connecting rod when the variable element is heated.