Provided is a pneumatic tire with noise reducer, which can reduce the cost for manufacturing a noise reducer and which can keep the effect to suppress cavity resonance. The pneumatic tire with noise reducer 1 comprises a pneumatic tire 3 and a noise reducer 7 attached to a tire cavity surface 6 of the tire. The noise reducer 7 is formed into a ring shape by butting both end faces 12e of elongated sponge material 12 disposed along the tire circumferential direction. In the noise reducer 7, moreover, a butt-joint face 8 formed by butting both of the end faces 12e of the sponge material 12 is a substantive plane.