The present invention provides a medical fluid injector connected to a supply tube through which medical fluid is supplied and a discharge tube through which the medical fluid is discharged, so as to store and discharge the medical fluid. The medical fluid injector has a housing body which forms an outer body, and a reservoir module which is disposed within the housing body and stores and discharges the medical fluid. The housing body has a grip portion, which forms a portion of an outer peripheral surface of the housing body and has a length in the longitudinal direction that is greater than a width in a direction orthogonal to the longitudinal direction, and a pair of button protection arms located at one end adjacent to the grip portion. The reservoir module is fixed to the housing body within the housing body. The reservoir module has a reservoir bag, which stores and discharges the medical fluid, and a push button which pushes the reservoir bag to discharge the medical fluid in the reservoir bag. The reservoir bag is fluidically connected to the supply tube and the discharge tube. A portion of the push button is positioned between the button protection arms. The push button is movable along a central axis of the housing body.
