PURPOSE: To relieve a semiconductor pellet of a non-defective product and to improve yield of a semiconductor device in an assembling process by recognizing, deciding a lead frame having a defect in its shape before the pellet is placed, and eliminating placing of the pellet of the non-defective product in the lead frame having the defect in its shape.

CONSTITUTION: A lead frame 2 supplied from a frame supply unit 10 to a conveying route 11 is recognized in its shape by a picture recognition camera 12 at a front stage to be conveyed to a pellet bonding unit 17, and propriety of its shape is decided by a frame propriety deciding circuit 13. If the shape of the frame 2 is decided to be a non-defective product, a semiconductor pellet 4 is placed on a surface of a tab 2A of the frame 2. On the contrary, if it is decided to be defective, a signal for stopping the unit 17 is output to an arm drive controller 14, and the pellet 4 is not placed on the surface of the tab 2A of the frame 2. Thus, the pellet 4 of the non-defective product can be relieved.