A holding device for holding a cooling fan comprising: a duct having a hollow in which a cooling fan is to be fitted; a stopper portion which keeps one operative end of the cooling fan from further moving to hold the cooling fan at a fitting position; and a plurality of elastic wall segments formed in a cooling fan insertion end of a wall of the duct; wherein each of some of the plurality of elastic wall segments is formed with a locking claw for keeping the other operative end of the cooling fan from moving. With this construction, the cooling fan 31 can be more surely mounted in a duct. Consequently, vibration reduction effect and sound reduction effect with respect to the cooling fan is improved.