An electric power steering electric motor apparatus comprising: an electric motor comprising: a motor housing ; a stator that is held by said motor housing ; a rotor that is disposed inside said stator so as to be rotatably supported by said motor housing ; and a power supplying portion that is connected to said stator to supply electric power; and a controlling unit comprising: a driving circuit that supplies electric power to said electric motor ; a connecting portion that is connected to said power supplying portion ; a controlling circuit that controls said driving circuit ; and a case that covers said driving circuit and said controlling circuit , said electric motor and said controlling unit being mounted coaxially onto a gear housing , housing a speed reducing mechanism that reduces rotational speed of said electric motor so as to position said controlling unit on a side near said gear housing , wherein said connecting portion is positioned and held by an insulating member so as to be insulated from said case and said motor housing , said electric power steering electric motor apparatus being characterized in that : said connecting portion is joined to said power supplying portion inside said case through an opening portion that is formed on said case . a motor housing ; a stator that is held by said motor housing ; a rotor that is disposed inside said stator so as to be rotatably supported by said motor housing ; and a power supplying portion that is connected to said stator to supply electric power; and a controlling unit comprising: a driving circuit that supplies electric power to said electric motor ; a connecting portion that is connected to said power supplying portion ; a controlling circuit that controls said driving circuit ; and a case that covers said driving circuit and said controlling circuit , said electric motor and said controlling unit being mounted coaxially onto a gear housing , housing a speed reducing mechanism that reduces rotational speed of said electric motor so as to position said controlling unit on a side near said gear housing , wherein said connecting portion is positioned and held by an insulating member so as to be insulated from said case and said motor housing , said electric power steering electric motor apparatus being characterized in that : said connecting portion is joined to said power supplying portion inside said case through an opening portion that is formed on said case . a driving circuit that supplies electric power to said electric motor ; a connecting portion that is connected to said power supplying portion ; a controlling circuit that controls said driving circuit ; and a case that covers said driving circuit and said controlling circuit , said electric motor and said controlling unit being mounted coaxially onto a gear housing , housing a speed reducing mechanism that reduces rotational speed of said electric motor so as to position said controlling unit on a side near said gear housing , wherein said connecting portion is positioned and held by an insulating member so as to be insulated from said case and said motor housing , said electric power steering electric motor apparatus being characterized in that : said connecting portion is joined to said power supplying portion inside said case through an opening portion that is formed on said case . <EOS>