A wired-circuit-board assembly sheet includes a plurality of wired circuit boards and a supporting sheet for supporting the wired circuit boards in an aligned state. Each of the wired circuit boards includes a distinguishing mark forming portion to be formed with a distinguishing mark for distinguishing between defectiveness and non-defectiveness of the wired circuit board. The distinguishing mark forming portion is divided by a weir portion for preventing the distinguishing mark from flowing out from the distinguishing mark forming portion.