Introduction Paraganglioma of the urinary bladder is a very rare disease accounting for 0.06% of all bladder tumors. Owing to their rarity and symptomatic variability, preoperative diagnosis is often difficult. Case presentation A 70‐year‐old male was referred to our department for hematuria. Cystoscopy showed a non‐papillary broad‐based tumor. Computed tomography and magnetic resonance imaging revealed a 32‐mm bladder tumor at the top of the bladder, which suggested muscle‐invasive bladder tumor. We diagnosed muscle‐invasive bladder cancer or urachal carcinoma, and transurethral resection of the bladder tumor was performed. At the initiation of transurethral resection of the bladder tumor, the systolic blood pressure was elevated to over 200 mmHg. The pathological findings revealed paraganglioma of the urinary bladder, and afterward, a partial cystectomy was performed. Conclusion We herein reported the case of paraganglioma in the bladder whose blood pressure became extremely elevated during transurethral resection of the bladder tumor. In addition, we analyzed important factors for preoperative diagnosis using 162 cases reported in Japan.