In this paper, we proposed a method of 3D-US reconstruction with a bi-plane transrectal ultrasound (TRUS) probe for a 3D guidance of focal therapy without using a position sensor. The bi-plane TRUS probe, which has two transducer arrays, can provide two orthogonal cross-section images simultaneously. The proposed method compensates the prostate motion due to pressure during sweeping the TRUS probe. In phantom and cadaver experiments to evaluate the accuracy of the reconstruction, the proposed method has shown to have accuracy equal to or higher than position sensor-based reconstruction. These results suggest that the proposed method has potential usefulness in a clinical situation.