Provided are a tread rubber composition that provides a balanced improvement of fuel economy, fracture strength, and abrasion resistance, and a pneumatic tire including the rubber composition. The present invention relates to a tread rubber composition including: a rubber component; a silica having a nitrogen adsorption specific surface area of 220 m2/g or more; and a mercapto silane coupling agent, the tread rubber composition satisfying the following relationship (A): (A)G*(4%)−G*(64%)≤150[kPa] wherein G*(4%) is the shear modulus at an applied strain of 4% at 100° C., and G*(64%) is the shear modulus at an applied strain of 64% at 100° C.