A projection device includes a light source module, an optical engine module, a projection lens, a housing, and at least one first heat dissipating element. The housing comprises a first end and a second end opposite to each other. The at least one first heat dissipating element is disposed in the housing, and each of the at least one first heat dissipating element includes a first plate portion, a second plate portion, and a first fin portion. The first plate portion is connected to the light source module. The second plate portion is connected to the first plate portion. The first fin portion is connected to the second plate portion and includes a plurality of first fins arranged at intervals. These first fins are arranged between the first end and the second end.