Webbing take-up device

In a webbing take-up device, a housing chamber is provided integrally at an axial-direction end portion of the spool, and opens to an outer-side in a radial-direction of the spool. A lock plate is housed in the housing chamber, and a side surface of the housing chamber is engaged with the lock plate at a predetermined occasion, and rotation of the spool in a drawing-out direction is regulated. An opening-side end portion of the side surface is arranged at a position away from a slit in a circumferential-direction of the spool. Thus, a wall part passing the side surface and being along the axial-direction becomes larger, so strength of the spool can be enhanced. Further, an outer-side of the housing chamber in the axial-direction is closed, so strength of the housing chamber can be enhanced, with the result that the strength of the spool can be further enhanced.