In 1118, he was born in Ubushina, Ise no kuni (Ubushina, Ise Province, which is currently Ubushina, Tsu City, Mie Prefecture) as the first son of TAIRA no Tadamori, who was the head of the Ise branch of the Taira clan.
元永元年（1118年）、伊勢平氏の頭領である平忠盛の嫡子として伊勢国産品（うぶしな、現在の三重県津市産品）で生まれる。