The present invention provides a medical injection device having the following effects: the container containing an injection solution and an agitation means provided in the container are vibrated to agitate the injection solution, so as to allow a target substance contained in the injection solution to be injected at a uniform concentration with being sufficiently agitated, and thereby a fatal medical accident that may be caused by an nonuniform concentration of the target substance may be prevented; the container and the filter and/or an expansion tube are connected with each other through an injection solution level controller, such that a level and an injection rate of the injection solution filled therein may be more freely controlled; and in particular, in order to allow the injection solution to be subjected to a sediment filtration process inside the filter, the injection solution is injected while being filled in the filter at a preset level or more, thereby the target substance such as the stem cells may be stably filtered and injected without damage due to an injection solution filter medium, etc.