The present disclosure provides an incubator capable of enabling a user to easily and sufficiently perform a required operation inside an infant accommodation space of the incubator, since substantially the entire area of a hand insertion opening is actually opened when the user opens a service door and inserts their hand into the hand insertion opening. In the incubator, the hand insertion opening is configured so as to be capable of being opened and closed by the service door in a first state in which a first support frame member is attached to a peripheral wall section of the infant accommodation space, and the hand insertion opening is configured so as to be capable of functioning as an aperture window in a second state in which a second support frame member, a third support frame member, and an aperture window forming member are respectively attached to the peripheral wall section.
