BASE TREAD RUBBER COMPOSITION AND PNEUMATIC TIRE

PROBLEM TO BE SOLVED: To provide a base tread rubber composition capable of achieving a well balanced improvement in low fuel consumption and rupture strength, and to provide a pneumatic tire using the same.SOLUTION: The present invention relates to a base tread rubber composition containing rubber constituent, silica and compound of the following formula (I), in which the content of a conjugated diene-based polymer obtained by reacting a particular aminosilane compound to one end of the conjugated diene-based polymer having a constitutional unit based on conjugated diene and a constitutional unit based on compound of the following formula (1) and in which the content of the monomer unit based on compound of the following formula (1), assuming the total amount of monomer units in the conjugated diene-based polymer as 100 mass%, is 0.01 to 20 mass%, in 100 mass% of the rubber constituent is 5 mass% or more, the content of the silica for 100 pts.mass of the rubber constituent is 5 to 150 pts.mass, and the content of compound of the following formula (I) for 100 pts.mass of the rubber constituent is 3 to 25 pts.mass.