A mixing apparatus for mixing a first component and a second component comprises: a first vessel which has a negative internal pressure and houses the first component a second vessel which houses the second component and a double-ended needle which allows communication between the first vessel and the second vessel when a first stopper element and a second stopper element have been pierced through by the needle. Penetration-resistance increasing parts which have a greater penetration resistance with respect to the first stopper element and the second stopper element than tip end tubes are respectively provided on a first puncture needle and a second puncture needle of the double-ended needle at positions further towards the base end than the tip end tubes. The axial heights of the edge faces of the tip end tubes are both less than the thicknesses of the first stopper element and of the second stopper element.
