An electronic device includes a body, a detector window, and a fixing mechanism for securing the detector window to the body. The detector window is capable of being inserted into the body in a first direction, and includes at least one hook member. The fixing mechanism includes at least one latching member, at least one first limiting member and at least one second limiting member. The at least one latching member hooks the at least one hook member to limit the movement of the detector window in the first direction. The at least one latching first limiting member and the at least one second limiting member respectively are arranged opposite sides of the latching member and respectively resisting against opposite sides of the at least one hook member to cooperatively limit the movement of the detector window in a second direction perpendicular to the first direction.