The present invention relates to an automatic multifunctional liquid injector having a separation type operation device and enabling: an operation unit to be combined thereto in a replaceable manner such that an operation can be performed by selectively mounting a hydrolifting operation unit and a filler operation unit according to a procedure； and set values to be input, in accordance with each operation, into a control means of a syringe driving unit such that the optimum set value is selected through a user's selection, thereby enabling an effective procedure.
