Abstract: Improved, compact apparatus for use in inhaling pharmaceutical aerosols. The apparatus increases aerosol deposition to the bronchiolus while it limits deposition in the oropharynx. The volumetric flow rate is limited by the use of orifices in the far end of the rigid holding chamber. The invention is also designed to make it easy for the patient to inhale the medication at the proper point in his respiratory cycle. Besides the rigid holding chamber the apparatus of the invention utilizes a unique and compact integrated flow meter to deliver to the patient a volume of unmedicated ambient air before the inhalation of the medicine containing aerosol. When the apparatus is not in use, it folds up, so that some of the integrated flow meter apparatus, and the mouthpiece are located inside the rigid holding chamber thereby minimizing the size of the device.