To investigate whether intrarectal local anesthesia with heated lidocaine gel (IRLAH) is non-inferior to periprostatic nerve block (PNB) for reducing pain in patients undergoing transrectal ultrasound (TRUS)-guided prostate biopsy. We performed a randomized controlled non-inferiority trial with 100 participants who underwent systematic TRUS-guided, 12-core prostate biopsy from August 2019 to July 2020. These participants were randomly assigned to a group receiving intrarectal local anesthesia with 20 mL of heated (40°C) 2% lidocaine gel (n = 50) or PNB (n = 50). The primary outcome was a pain score on a 0-10 visual analogue scale (VAS) at four time points with the non-inferiority margin of 1; VAS-1: during local anesthesia application; VAS-2: during probe insertion; VAS-3: during biopsy; VAS-4: 30 minutes after the procedure. The secondary outcome included complications during and after the procedure. The IRLAH group (0.1) met non-inferiority as well as superiority criteria for mean VAS-1 score vs. the PNB group (2.33) (P < 0.001), as the difference (95% confidence interval [CI]) between the two groups was -2.23 (-2.66 to -1.79) and the upper bound of the 95% CI were both below the prespecified non-inferiority margin and below zero. For mean VAS-3 score, the difference (95% CI) was 0.3 (-0.38 to 0.98) and the upper bound of the 95% CI did not exceed the predefined non-inferiority margin indicating that IRLAH was non-inferior (IRLAH group, 3.44; PNB group, 3.14). Also, non-inferiority was shown for pain scores at VAS-2 and VAS-4. There were no significant differences in complications. IRLAH is a noninvasive and non-inferior alternative to PNB for pain control in TRUS-guided prostate biopsy without increased risk of complications.