An object is to provide a medical liquid infusion apparatus suitable for a portable use and capable of suppressing an abrupt change in flow rate even when the environmental temperature rises. A medical liquid infusion apparatus 1 is provided with a driving portion 2 and configured to infuse a medical liquid inside a medical liquid container 3 to a patient by applying a pressure to the medical liquid container 3 using a driving force of the driving portion. The driving portion 2 includes a compressed gas cylinder 4 filled with a compressed gas, and it is configured in such a manner that the driving force is generated by the pressure inside the compressed gas cylinder 4.