A webbing take-up device comprising: a spool that takes up webbing worn by an occupant by being rotated in a take-up direction; and a pretensioner mechanism that includes a gas generator that includes a gas-generating-agent-storing portion in which a gas-generating agent is stored, and an ignition-device-storing portion provided with an ignition device that ignites the gas-generating agent, a gas-generator-attached portion to which the gas generator is attached, and that includes a gas-supplied portion into which gas generated by the gas generator is supplied, and a discharge portion that is provided to a portion of the gas-generator-attached portion where the ignition-device-storing portion is disposed, and through which gas supplied into the gas-supplied portion is discharged; the pretensioner mechanism being configured to rotate the spool in the take-up direction due to actuation of the gas generator in a vehicle emergency, wherein the gas-generator-attached portion includes a first tubular portion having an open end, an inner diameter of the first tubular portion being larger than an outer diameter of the ignition-device-storing portion, wherein the ignition-device-storing portion is fixed in a state held between a swaged portion formed at the open end side of the gas-generator-attached portion and an end face on the first tubular portion side of the gas-supplied portion, and wherein the gas-supplied portion is formed by a second tubular portion that abuts the ignition-device-storing portion, an inner diameter of the second tubular portion being smaller than the inner diameter of the first tubular portion, characterized in that the discharge portion is formed in the first tubular portion, and in that a passage is formed between the end face on the first tubular portion side of the second tubular portion and the ignition-device-storing portion of the gas generator. a spool that takes up webbing worn by an occupant by being rotated in a take-up direction; and a pretensioner mechanism that includes a gas generator that includes a gas-generating-agent-storing portion in which a gas-generating agent is stored, and an ignition-device-storing portion provided with an ignition device that ignites the gas-generating agent, a gas-generator-attached portion to which the gas generator is attached, and that includes a gas-supplied portion into which gas generated by the gas generator is supplied, and a discharge portion that is provided to a portion of the gas-generator-attached portion where the ignition-device-storing portion is disposed, and through which gas supplied into the gas-supplied portion is discharged; a gas generator that includes a gas-generating-agent-storing portion in which a gas-generating agent is stored, and an ignition-device-storing portion provided with an ignition device that ignites the gas-generating agent, a gas-generator-attached portion to which the gas generator is attached, and that includes a gas-supplied portion into which gas generated by the gas generator is supplied, and a discharge portion that is provided to a portion of the gas-generator-attached portion where the ignition-device-storing portion is disposed, and through which gas supplied into the gas-supplied portion is discharged; the pretensioner mechanism being configured to rotate the spool in the take-up direction due to actuation of the gas generator in a vehicle emergency, wherein the gas-generator-attached portion includes a first tubular portion having an open end, an inner diameter of the first tubular portion being larger than an outer diameter of the ignition-device-storing portion, wherein the ignition-device-storing portion is fixed in a state held between a swaged portion formed at the open end side of the gas-generator-attached portion and an end face on the first tubular portion side of the gas-supplied portion, and wherein the gas-supplied portion is formed by a second tubular portion that abuts the ignition-device-storing portion, an inner diameter of the second tubular portion being smaller than the inner diameter of the first tubular portion, characterized in that the discharge portion is formed in the first tubular portion, and in that a passage is formed between the end face on the first tubular portion side of the second tubular portion and the ignition-device-storing portion of the gas generator.