A method for producing a steel tube for air bag, characterized in subjecting a steel tube having a wall thickness of 4.0 mm or less to quenching treatment in which the steel tube is rapidly cooled after high-frequency induction heating, the method comprising: subjecting the steel tube to the high-frequency induction heating in such a manner that an outer surface temperature T1 (°C) of steel tube measured at the end of high-frequency induction heating is within the range defined by Formula; by using the outer surface temperature of steel tube thus measured, calculating time x (second) elapsed from when the outer surface temperature of steel tube reaches the temperature of Ac 3 transformation point in the process of high-frequency induction heating to when the outer surface temperature of steel tube is measured; and based on the calculated time x (second), controlling a period of time t (second) required from the measurement of the outer surface temperature of steel tube to the start of rapid cooling so that the time t (second) is within the range defined by Formula; wherein the time x (second) is calculated by Formula: TAc 3 + 40 ° C ≤ T 1 ≤ 1100 ° C 0 sec < t ≤ 10 sec − x x = T 1 − TAc 3 / v where TAc3 is the temperature (°C) of Ac 3 transformation point and v is a heating rate (°C/s) derived by dividing the difference between the outer surface temperatures (°C) of the steel tube measured at the end of the heating and at the beginning thereof by the heating time (s), and wherein the steel tube has a chemical composition consisting, by mass%, of C: 0.05 to 0.25%, Mn: 0.05 to 2.50%, Si: 0.1 to 1.0%, Cu: 0.01 to 0.80%, Ni: 0.01 to 0.80%, Cr: 0.01 to 1.20%, Mo: 0.01 to 1.00%, and optionally B: 0.05% or less, Ti: 0.10% or less, and Nb: 0.10% or less, the balance being Fe and impurities. subjecting a steel tube having a wall thickness of 4.0 mm or less to quenching treatment in which the steel tube is rapidly cooled after high-frequency induction heating, the method comprising: subjecting the steel tube to the high-frequency induction heating in such a manner that an outer surface temperature T1 (°C) of steel tube measured at the end of high-frequency induction heating is within the range defined by Formula; by using the outer surface temperature of steel tube thus measured, calculating time x (second) elapsed from when the outer surface temperature of steel tube reaches the temperature of Ac 3 transformation point in the process of high-frequency induction heating to when the outer surface temperature of steel tube is measured; and based on the calculated time x (second), controlling a period of time t (second) required from the measurement of the outer surface temperature of steel tube to the start of rapid cooling so that the time t (second) is within the range defined by Formula; wherein the time x (second) is calculated by Formula: TAc 3 + 40 ° C ≤ T 1 ≤ 1100 ° C 0 sec < t ≤ 10 sec − x x = T 1 − TAc 3 / v where TAc3 is the temperature (°C) of Ac 3 transformation point and v is a heating rate (°C/s) derived by dividing the difference between the outer surface temperatures (°C) of the steel tube measured at the end of the heating and at the beginning thereof by the heating time (s), and subjecting the steel tube to the high-frequency induction heating in such a manner that an outer surface temperature T1 (°C) of steel tube measured at the end of high-frequency induction heating is within the range defined by Formula; by using the outer surface temperature of steel tube thus measured, calculating time x (second) elapsed from when the outer surface temperature of steel tube reaches the temperature of Ac 3 transformation point in the process of high-frequency induction heating to when the outer surface temperature of steel tube is measured; and based on the calculated time x (second), controlling a period of time t (second) required from the measurement of the outer surface temperature of steel tube to the start of rapid cooling so that the time t (second) is within the range defined by Formula; wherein the time x (second) is calculated by Formula: TAc 3 + 40 ° C ≤ T 1 ≤ 1100 ° C 0 sec < t ≤ 10 sec − x x = T 1 − TAc 3 / v where TAc3 is the temperature (°C) of Ac 3 transformation point and v is a heating rate (°C/s) derived by dividing the difference between the outer surface temperatures (°C) of the steel tube measured at the end of the heating and at the beginning thereof by the heating time (s), and wherein the steel tube has a chemical composition consisting, by mass%, of C: 0.05 to 0.25%, Mn: 0.05 to 2.50%, Si: 0.1 to 1.0%, Cu: 0.01 to 0.80%, Ni: 0.01 to 0.80%, Cr: 0.01 to 1.20%, Mo: 0.01 to 1.00%, and optionally B: 0.05% or less, Ti: 0.10% or less, and Nb: 0.10% or less, the balance being Fe and impurities.