Rack device and incubator having the same

A rack device having a receiver that can be prevented from being separated from a rack post in an incubator. A rack device in which a receiver is mounted between a pair of rack posts to hold a rack on the receiver includes a pair of engaging hooks which are formed in the receiver and a plurality of engaging holes which are formed in both the rack posts and in which both of the engaging hooks of the receiver disengageably engage, respectively. The rack posts are configured to be able to change an interval there between and select a first state in which the engaging hooks can be disengaged from the engaging holes and a second state in which the movement of the receiver is restricted while the engaging hooks be kept to engage in the engaging holes by changing the interval between the rack posts.