A chassis module for fixing electronic devices includes a fixing chassis unit and a first movable chassis unit. The fixing chassis unit has a fixing chassis body and a first fixing retaining structure disposed on a first lateral wall of the fixing chassis body. The first movable chassis unit is detachably disposed in the fixing chassis body. The first movable chassis unit has a first movable chassis body, a first movable retaining structure disposed on a first lateral wall of the first movable chassis body and mated with the first fixing retaining structure, and at least one support element bent downwardly and extended from one lateral wall of the first movable chassis body. Therefore, after the first movable chassis unit is assembled in the fixing chassis unit, the support element provides support function for the first movable chassis unit to prevent the first movable chassis unit from inclining or collapsing.