목적: Intratympanic injection is widely used in the treatment of diseases such as sudden hearing loss, Meniere's disease, tinnitus. In generally it performed after local anesthesia to the ear drum surface. But some studies has said the pain suffered patients is not related to the degree of anesthesia. Eardrum is thin structure of 0.1mm, so it can be penetrate more thinner needle than the penetration needle is used for the percutaneous injection. Therefore, we studied for learn how deferent of degree of pain depending on size of injection needles. And also researched whether there is a difference in the degree of drug reflux, bleeding, healing of injection site. 방법:In patients who underwent an injection was performed on an outpatient basis and prospective single-blinded randomized study. Needle was used for 25G (diameter 0.508mm) and 30G ( diameter 0.305mm). It was mixed with two needles randomly injected four times per patient , and the patient didnt know what size of needles were used. Both processes are performed on different dates in a single experiment tied to one injection twice with each of the 25G and 30G. 38 Meeting experiments were performed . The degree of pain was measured visual analogue scale (VAS) divided by 100 characters. The result did not include the treatment of patients who discontinued. We performed to analyze sample T test for analysis a difference in the pain response 결과:When using a 30G of the patient feels pain(VAS) smaller than when using a 25G which was statistically significant(p=0.025) 결론:The thickness of the needle during intratympanic injection is performed affects the patient feels pain, the thickness of the thin needles The pain is reduced.