Provided are a cap tread and a passenger car tire which provide improved overall performance in terms of fuel economy and tensile strength at break while having good dimensional stability. Included is a cap tread of a passenger car tire, including a rubber composition A phase and a rubber composition B phase which are independent of and share a boundary with each other, the rubber composition A phase containing, per 100 parts by mass of the rubber components therein, 100 parts by mass or more of silica and 10 parts by mass or less of carbon black, the rubber composition B phase containing, per 100 parts by mass of the rubber components therein, 10 parts by mass or more of carbon black and 13 to 20 parts by mass of silica, the rubber composition B phase being divided by the rubber composition A phase to be independently present in the rubber composition A phase