With the advance of the ultrathin bronchoscope into the peripheral bronchi, however, the visibility of the small airway becomes limited. Therefore, in most cases when an ultrathin bronchoscope is used for performing a biopsy of peripheral pulmonary lesions, it is advanced under fluoroscopic guidance to approach the lesions. This is facilitated by careful tip manipulation of the bronchoscope in the peripheral airway. In our two cases, however, too forceful an advance and manipulation of the bronchoscope under fluoroscopic guidance led to visceral pleural perforation. In ultrathin bronchoscopy, firmly lodging the tip of the bronchoscope into the bronchus, the so-called “wedge technique,” can cause an adverse event. To reduce such injurious complications, manipulations with an ultrathin bronchoscope must be very gently performed, especially in the peripheral lung. Furthermore, to avoid coming too close to the visceral pleura, the position of the tip of the ultrathin bronchoscope should very often be confirmed by fluoroscopy, either by rotating the patient or the arm of a C-arm fluoroscope. The fluoroscopic findings were characteristic. After the ultrathin bronchoscope was passed through the visceral pleura, the tip motion was greater and more unstable than the motion in the peripheral endobronchus.