<p>A constant pharmaceutical infuser comprising a casing 12 having therein an airtight chamber 14 and a gas cylinder holding chamber 15; a pharmaceutical infusion solution filling container 18 capable of undergoing a decrease in internal volume upon application of pressure, provided in the airtight chamber 14 and having an outlet 19 that communicates with the outside of the casing and to which a hypodermic needle 23 is connected through a tube 21 and a flow rate control valve 22; a miniature gas cylinder held in the gas cylinder holding chamber 15 and capable of feeding a pressurized gas to the inside of the airtight chamber 14 when unsealed; and a pressure control valve 28 provided at a gas feed opening of the miniature gas cylinder 24, and capable of closing the gas feed opening when the gas pressure inside the airtight chamber 14 becomes higher than a given value and opening the gas feed opening when the gas pressure inside the airtight chamber 14 becomes lower than the given value. The gas in the miniature gas cylinder 24 flows into the airtight chamber 14 through the pressure control valve 28, whereupon the pharmaceutical infusion solution enclosed in the pharmaceutical infusion solution filling container 18 is forced out at a constant flow rate by the action of the gas pressure and is administered to a patient through the tube 21, the flow rate control valve 22 and the hypodermic needle 23. <IMAGE></p>
