The present disclosure provides a wavelength conversion device including a first thermal conductive plate, a wavelength conversion layer and a second thermal conductive plate. The wavelength conversion layer is disposed on the first side of the first thermal conductive plate and configured to perform a wavelength conversion. The second thermal conductive plate is disposed on the second side of the first thermal conductive plate. The first thermal conductive plate and the second thermal conductive plate are combined to conduct the heat generated by the wavelength conversion layer during the wavelength conversion. Since the thermal conductivity coefficients of the at least two thermal conductive plates are increased along the heat transferring path, it is advantageous to minimize the thermal resistance of the heat transferring path. Thus, the heat generated by the wavelength conversion layer during the wavelength conversion is dissipated along the heat transferring path to enhance the heat dissipation efficiency.