A medical fluid injector is connected to a supply tube through which medical fluid is supplied and a discharge tube through which the medical fluid is discharged. The medical fluid injector has a housing body and a reservoir module which is disposed within the housing body. The housing body has a grip portion, which 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 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.
