[Show abstract][Hide abstract] ABSTRACT: We have applied the terahertz time-domain spectroscopy (THz-TDS) to pathological diagnosis of prostate cancer. We measured THz absorption spectra and THz image of sliced samples which included prostate cancer and normal tissues. The samples were kept from drying out by sandwiching them by thin plastic plates sealed by vacuum grease. We found that the THz absorption of prostate cancer is smaller than that of normal tissues. Using THz absorption image we can distinguish between prostate and normal tissues. THz-TDS is a promising method to pathological diagnosis of prostate cancer.