<p>A large number of projection/recess sections (33) are continuously formed on the back side of a band saw blade. The projection/recess sections (33) each have a recess (35) to which and from which a backup guide (29) of a saw blade guide device (25) can be engaged and disengaged and have a projection (37) adjacent to the recess (35). The length of each projection/recess section (33) is not more than four times the maximum pitch of the tooth points of teeth (31).</p>
