Automatic external defibrillator

An automatic external defibrillator is configured to automatically perform a defibrillation process of applying an electric shock for defibrillation to a heart of a subject. The defibrillator includes: a processor; and a memory storing computer-readable instructions that, when executed by the processor, cause the defibrillator to operate, the operations including: receiving a physiological signal of a subject through the electrode pad; determining whether defibrillation processing is required based on the physiological signal; and determining whether the electrode pad is attached to the object and whether a predetermined operation has been performed on the automated external defibrillator. When defibrillation processing is required, the defibrillator cancels the defibrillation processing while maintaining an on-state of a power supply of the defibrillator in response to a determination result of whether the electrode pad is attached to the object and whether a predetermined operation has been performed on the