The invention relates to a bit holder for an earth working machine, in particular a road milling machine, having a support member onto which an insertion projection is indirectly or directly attached on an insertion projection side, the support member comprising two first and/or two second stripping surfaces that are at an angle to one another, and the support member having a working side that comprises a bit receptacle. In order to achieve a stable and long-lived configuration for such a bit holder, provision is made according to the present invention that the first and/or second stripping surfaces diverge from the insertion projection side toward the working side.