After inputting in the field "おまとめ請求代表回線 (the main line of "Omatome Seikyu Service (combined billing method)," please select the communications company from the pull-down menu in the field of "おまとめ請求お申し込み回線（代表回線以外）(the line (except the main line) for the application for "Omatome Seikyu Service")" and input the phone number or billing number.

You can't register NTT docomo lines as sub-lines with "Omatome Seikyu Service (combined billing method)."

If you have multiple docomo lines, please apply for "Ikkatsu Seikyu Service (single billing service)."

Click "here" for applications for Ikkatsu Seikyu Service