MIrabegron With oveRACtive bLadder Symptoms in mEn

Inclusion Criteria: * Male aged 20 years * Patients with an average of at least 8 micturitions per 24 hours in last 3 days based on the micturition diary * Patients with an average of at least 1 episode of urgency per 24 hours in last 3 days based on the micturition diary * Patients who have symptoms of OAB for at least 12 weeks prior to the enrollment * Patients who are able to complete the micturition diary and questionnaires correctly * Patients who provided a singed consent form after being informed of the nature of the study and risk and benefit of the study treatment. Exclusion Criteria: * Patients with AUR history * Patients with PSA ≥ 10 ng/ml or suspected prostate cancer * Patients who have an average total daily urine volume ≥ 3000 mL * Patients with suspected stress incontinence * Patients with PVR ≥200 ml or Qmax ≤5ml/sec * Patients who have used according to the criteria below: * Patients who began or discontinued the drug(s) or changed the dose within 4 weeks before enrollment * Patients who were treated with an anticholinergic agent, 5-aplha reductase inhibitor within 4 weeks before enrollment * Patients who began or discontinued 5ARI treatment or changed the dose within 6 months * Patients began or has changed a bladder training program or pelvic floor exercises less than 4 weeks prior to Screening. * Patients who had an indwelling catheter or practices intermittent self-catheterization * Patients who received surgical treatment that may influence urinary track function (TURP, laser therapy, etc.) within 24 weeks of run-in period * Uncontrolled hypertension: SBP ≥180 mmHg, DBP ≥110 mmHg * Pulse rate ≥110 bmp or \<50 bpm * Patients with complications of urinary tract infection, urolithiasis and interstitial cystitis or past history of recurrent urinary tract infection * Patients with hypersensitivity to β-adrenergic receptor agonists or anticholinergics * Patients has a clinically significant ECG abnormality, as determined by the Investigator