FRICTION STIR PROCESSING DEVICE AND FRICTION STIR PROCESSING METHOD

PROBLEM TO BE SOLVED: To provide a friction stir processing device and a friction stir processing method, allowing a certain travel start of a tool at a time point when workpieces are friction stirred into a proper softened state.SOLUTION: The friction stir processing device 1 includes: the tool 20; a rotary driving means 32 of the tool 20; a vertical movement driving means 85 of the tool 20; a transfer driving means 83 of the tool 20; a detection means 50 detecting a pressing resistance force F received from the workpieces W1, W2 by the tool 20 in the axial direction of the tool 20 when pressing the workpieces W1, W2 while the tool 20 rotates; and a control means 5. When the pressing resistance force F reaches a preset transfer start set value S or a preset delay time after time t2 when the pressing resistance force F has reached a maximum value P, which is decided by the control means 5 when the tool 20 is pressed on the workpieces W1, W2 while the tool 20 rotates, the control part 5 makes the tool 20 start to relatively move in a processing direction of the workpieces W1, W2.