An auxiliary appliance, known as a mitering device, for setting the cutting angle in miter-cutting operations prior to the cutting proper, comprising two arms (1, 2), which are pivotally interconnected by means of a hinge, each one of said arms having at least one orientation face, and an angle-indicating means (4), which is connected to the arm-interconnection hinge via a gear mechanism (5), said gear mechanism being adapted, upon relative pivotal motion of the arms, to transfer essentially half of said pivotal motion to the angle-indicating means relative to the arms.