PROBLEM TO BE SOLVED: To prevent welding waste from remaining on an end edge in a CD direction of a sheet-like member and suppress defects such as abrasion and breakage which may occur when a horn into which ultrasonic energy is input is brought into contact with an anvil.SOLUTION: An ultrasonic welding apparatus performs ultrasonic welding processing on a sheet-like member 1a transferred while being wound around an outer peripheral surface 30s of a rotary member 30 rotating around a central axis. An ultrasonic processing unit includes a horn 61 vibrating with ultrasonic wave and an anvil 71 sandwiching the sheet-like member. The outer peripheral surface of the rotary member includes each section in which each end of the sheet-like member should be positioned. The ultrasonic welding apparatus includes an ultrasonic energy adjustment section which starts to reduce ultrasonic energy input per unit length in the CD direction in a case in which an ultrasonic processing member passes through a second section if a section through which the ultrasonic processing member in each section passes at the time when the ultrasonic processing member starts to traverse the sheet-like member in the CD direction is defined as a first section, and a section through which the ultrasonic processing member passes at the time when the ultrasonic processing member finishes traversing is defined as the second section.【課題】シート状部材のＣＤ方向の端縁に溶着屑が残留することを防ぎ、超音波エネルギーを投入するホーンがアンビルに接触することで起こり得る摩耗や破損などの不具合を抑制する。【解決手段】中心軸回りに回転する回転部材３０の外周面３０ｓに巻き付けられながら搬送されるシート状部材１ａに超音波溶着処理を行う超音波溶着装置である。超音波処理ユニットは、超音波振動するホーン６１とシート状部材を挟み込むアンビル７１を有する。前記回転部材の前記外周面は、シート状部材の前記各端部が位置すべき各区間を有し、各区間の前記超音波処理部材がＣＤ方向に前記シート状部材を横切り始めるときに通過する区間を第１区間とし、横切り終えるときに通過する区間を第２区間とした場合に、前記超音波処理部材が第２区間を通過しているときに、ＣＤ方向の単位長さ当たりに投入する超音波エネルギーを減らし始める超音波エネルギー調整部を有している。【選択図】図１０Ａ
