The invention discloses a projection device. The projection device comprises a body, an auxiliary bracket, a door cover and a third connecting component, wherein the body has a mounting part, and the auxiliary bracket is connected with the body through a first connecting component; the door cover is connected with the body through a second connecting component, and the first connecting component and the second connecting component are overlapped or parallel; the third connecting component is connected with the door cover and the auxiliary bracket; the door cover is in a closed state when being located at a first position; when moving towards a second position, the door cover drives the third connecting component to be deformed, the auxiliary bracket does not move relative to the body, and when the door cover reaches the second position, the third connecting component reaches a deformation limit; and when the door cover moves to a third position, the door cover drives the auxiliary bracket to move through the third connecting component, and the auxiliary bracket moves relative to the body through the first connecting component, so as to expose the mounting part. According to the projection device, the door cover and the auxiliary bracket do not need to be dismounted one by one when elements are exchanged, so that the exchanging difficulty is reduced, and the working efficiency is improved.