There is provided a tire noise reduction device and a pneumatic tire, in which weight can be reduced while sound absorbing characteristics are maintained and durability is improved.The tire noise reduction device 1A of the present invention includes a sound absorbing member 3 of flexible polyurethane foam to be attached to an inner surface of a tire facing a cavity of the tire. The sound absorbing member 3 comprises a first sound absorbing layer 3A placed on a tire inner surface side thereof. The first sound absorbing layer 3A has a tear strength (N/cm) per unit density (kg/m3) which is equal to or more than 0.30. The second sound absorbing layer 3B has a density which is lower than that of the first sound absorbing layer 3A.