The present invention addresses the problem of providing a chemical ablation device that can perform, in a simple manner, a chemical ablation treatment including electric potential measurements before and after the treatment. This chemical ablation device comprises: an electrode-equipped guidewire (30) capable of measuring the intracardiac electric potential； an over-the-wire balloon catheter (40) having a guidewire lumen (415) into which the electrode-equipped guidewire (30) is inserted； a Y-shaped connector (50) connected to the rear end side of the balloon catheter (40), and having a guidewire port (51) and an extension port (53)； and a hemostasis valve (60) connected to the guidewire port (51) of the Y-shaped connector (50), and provided with a side injection tube (65) that supplies ethanol to the guidewire lumen (415) of the balloon catheter (40). The ethanol supplied to the guidewire lumen (415) of the balloon catheter (40) is injected through an opening in a distal end tip (47).本發明的課題為提供可簡便地進行包含治療前後之電位測量的化學消融治療之化學消融裝置。本發明的化學消融裝置，具備：附電極導引線(30)，其可測量心內電位；全穿越線型之氣囊導管(40)，其具有供該附電極導引線(30)插通的導引線內腔(415)；Y字連接管(50)，其連接於該氣囊導管(40)的後端側且具有導引線通口(51)與擴張通口(53)；止血閥(60)，其具備：連接於該Y字連接管(50)之導引線通口(51)且對氣囊導管(40)之導引線內腔(415)供給乙醇的側注管(65)，將供給至氣囊導管(40)之導引線內腔(415)的乙醇，從前端細管(47)的開口噴射出來。
