Vehicle air conditioning unit

A vehicle air conditioning unit (S1) includes: a slide door (3a) which controls an opening ratio of an opening (1h, li) allowing an air stream to flow therethrough; a deflection suppressing portion (4) which suppresses a deflection of the slide door (3a) by pressing the slide door (3a); and a vibration suppressing portion (5) which suppresses the amplitude of a vibration of the slide door (3 a) generated when the slide door (3a) is exposed to the air stream.