Abstract: A projection device includes a casing structure and a protective mesh structure. The casing structure includes a casing, at least one position-limiting structure, and at least one stopper structure. At least one position-limiting groove is formed between a side cover of the casing and the position-limiting structure. The stopper structure is connected to the side cover and protrudes toward a containing space inside the casing. The protective mesh structure includes a protective mesh body and at least one protective mesh position-limiting portion. The protective mesh body is adapted to be installed in the containing space and at least partially limited in the position-limiting groove. The protective mesh position-limiting portion is connected to the protective mesh body and leans against the stopper structure of the casing structure, so as to prevent the protective mesh structure from being separated from the casing structure.