The present invention provides: a heat generation method that makes the first use of the ionic vacancies that are a by-product of an electrochemical reaction and have conventionally been left unreacted; and a device for implementing the same. The present invention pertains to: a heat generation method characterized by comprising colliding, in an electrochemical reaction that proceeds in an electrolysis cell, ionic vacancies having a positive charge generated at an anode and ionic vacancies having a negative charge generated at a cathode; and a heat generation device characterized by being equipped with an electrolysis cell provided with an anode and a cathode and an electrolyte solution accommodated within the electrolysis cell, and by generating heat by colliding ionic vacancies of opposite signs generated by causing the electrochemical reaction to proceed in the electrolysis cell via the anode and the cathode.