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).
