A vapor heating implement satisfies: (A) the content of water in the heating implement is equal to or higher than 40 parts by mass and is equal to or lower than 80 parts by mass for 100 parts by mass of the oxidizable metal (B) the content of the water-retention agent in the exothermic composition is equal to or higher than 0.3 parts by mass and is equal to or lower than 20 parts by mass for 100 parts by mass of the oxidizable metal (C) the content of water contained in the exothermic layer (121A) is equal to or higher than 8 parts by mass and is equal to or lower than 45 parts by mass for 100 parts by mass of the oxidizable metal and (D) the content of water contained in the water-retention sheet (121C) is from 15 to 30 mass% of the maximum water absorption of the water-retention sheet.온열구는 (A) 온열구에 함유되는 수분량이, 피산화성 금속 100 질량부에 대하여, 40 질량부 이상 80 질량부 이하, (B) 보수제의 함량이 피산화성 금속 100 질량부에 대하여, 0.3 질량부 이상 20 질량부 이하, (C) 발열층 (121A) 에 함유되는 수분량이, 상기 피산화성 금속 100 질량부에 대하여, 8 질량부 이상 45 질량부 이하, (D) 보수 시트 (121C) 에 함유되는 수분량이, 보수 시트의 최대 흡수량의 15 ∼ 30 질량% 이다.
