A projection apparatus includes a light valve, a projection lens, and a light source device. The light source device provides an illumination beam and includes a casing, a light source, and a wavelength-converting module. The casing has an opening portion. The light source device is disposed in the casing and provides an excitation beam. The wavelength-converting module is disposed at the opening portion and includes a bracket, a motor, and a wavelength-converting wheel. Heat-dissipating fin set of the bracket is exposed out of the casing via the opening portion. The motor is disposed on a carrying portion of the bracket. The wavelength-converting wheel is driven to rotate by the motor. The wavelength-converting wheel converts the excitation beam into a conversion beam. The illumination beam includes the conversion beam. The light valve is disposed on a transmissive path of the illumination beam to convert the illumination beam into an image beam.