Disclosed is an attachment member for a multiple-spindle head, which is used for attaching the multiple-spindle head to a quill of a drilling machine, a tapping machine or the like. This attachment member is attached to the quill through a cylinder having an attachment flange, and the attachment member includes a driving gear which is arranged so that when the attachment member is attached to the quill, the gear falls in engagement with a spindle in the quill and it is rotated by the spindle. The attachment member is used in the state where it is built in the multiple-spindle head, and in this state, gears for rotating drills, taps or the like attached to the multiple-spindle head are engaged with the driving gear through intermediate gears. At the time of exchange of the multiple-spindle head, the head is dismounted from the cylinder together with the attachment member, and another multiple-spindle head with which another attachment member has been combined in advance is attached to the cylinder instead.