Fixing device for narrow space

The invention discloses a fixing device for a narrow space. The fixing device comprises a supporting seat, a connecting seat and a movable assembly. The supporting seat comprises a supporting face. The connecting seat is provided with sliding rails and external holes. The movable assembly is provided with a pressing piece and sliding pieces, the pressing piece is provided with an inclined face facing the sliding pieces, and a pressing space is formed between the lower surface of the pressing piece and the supporting face. The sliding pieces are connected with the sliding rails in a slidable mode, an internal thread hole with an internal thread is formed in each sliding piece, and the sliding pieces are pressed on the inclined face. A rotating rod is connected to the external connection holes in a rotatable mode and is screwed with the internal threaded holes. When the rotating rod is rotated, the sliding pieces can slide along the sliding rails, the sliding pieces are pressed on different parts of the incline