A carbon heat source (10) is equipped with: a cylindrical section (11) provided with a cavity (11A) through which there is ventilation communication in the longitudinal axis direction (L) of the carbon heat source (10); and an ignition end (12) which is provided further to the ignition side of the carbon heat source (10) than the cylindrical section (11). Therein, a groove (12A) which connects with the cavity (11A) is formed on the end surface (E) of the ignition side of the ignition end (12).