In a biological signal utilizing appliance, an appliance control section controls the appliance in accordance with user's manipulation. At that time, an operation content is presented to a user through an operation presentation section. A biological signal detection section measures user's biological signal and detects from the biological signal the presence or absence of an event-related potential at the time point when time obtained by adding a predetermined shift time of approximately 150 ms to 600 ms elapses after a timing, as a starting point, when the operation content is presented. Upon detection of the event-related potential, a manipulation cancellation section instructs the appliance control section to cancel the presented operation content.