Heat generating method

A heat generating method comprising:

• heating, with a heater, a heat generating element and causing a first heat generating reaction in which the heat generating element generates heat with a first heat generation amount,
• wherein the heat generating element including:
• a base made of a hydrogen storage metal, a hydrogen storage alloy, or a proton conductor, and
• a multilayer film provided on a surface of the base,
• wherein the multilayer film having a stacked configuration including;
• a first layer made of a hydrogen storage metal or a hydrogen storage alloy and having a thickness of less than 1,000 nm, and a second layer made of a hydrogen storage metal or a hydrogen storage alloy, which is different from that of the first layer, or ceramics and having a thickness of less than 1,000 nm;
• triggering a second heat generating reaction in which the heat generating element generates heat with a second heat generation amount larger than the first heat generation amount, by imparting a perturbation to an input power to be applied to the heater in a state where the first heat generating reaction is occurring.