In a pretensioner device, a boot formed into a cylindrical shape covers a circumference of an elongated member, and a tip end of webbing inserted into an insertion hole of a joint anchor through a pair of through-holes formed on an upper end side of the boot is sewn at portions in front of and behind an insertion portion, whereby the boot is engaged with the elongated member. The insertion hole of the joint anchor is exposed to outside of the boot through the pair of through-holes of the boot even in a state in which the elongated member is covered with the boot. Therefore, positional shift of the boot relative to the webbing is prevented, and sewing operation of the webbing may be performed by inserting the tip end of the webbing into the insertion hole of the joint anchor after covering the elongated member with the boot.