A heating tool (100) according to the present invention includes a steam generator (10) that a heat generating layer (11) which contains an oxidizable metal, a carbon component, a water absorbent polymer, and water, and a water absorbent sheet (102) which carries water are laminated, and a bag (20) at least a portion of which has an air permeability and accommodates the steam generator (10), in which a mass ratio of the water absorbent sheet (102) is equal to or greater than 0.9 and equal to or less than 15 with respect to the water absorbent polymer contained in the heat generating layer (11).