The purpose of this study is to verify the efficacy and safety of acupuncture treatments (Individualized, Standardized acupuncture) for patients with knee osteoarthritis (OA).

The investigators targeted the patients with knee OA. After treatment in 4 groups - individualized acupuncture treatment, standardized acupuncture treatment, sham-needle treatment, and waiting groups - the investigators will compare the effects of pain relieving and daily performing improvement. So the investigators will confirm the efficacy of acupuncture, and further the best treatment method. In addition, the investigators are going to evaluate the safety of abnormal reaction during the treatment.

Inclusion Criteria:

1. At least 20 years of age, but below 80 years of age
2. Knee pain from OA in one or both knees in the last 3 months or more
3. Presence of knee OA diagnosed by an orthopedist based on American College of Rheumatology classification criteria
4. Knee pain from OA in one or both knees rated > 4 cm on a 10 cm Visual Analog Scale (VAS)
5. An understanding of the objectives and methods of the clinical trial, and willingness in completing the consent form.
6. Those who are reliable and willing to cooperate in this test, and obey the restrictions for the next 3 months

Exclusion Criteria:

1. Trauma to or surgery on the knee(s) within 6 months prior to enrollment, causing pain or functional problems
2. A history of prolotherapy, injection of hyaluronic acid or cortisone within the last 3 months
3. A physical or laboratory finding indicating infection, presence of an autoimmune disease, or inflammatory arthritis
4. Serious organic disease, and severe dysfunction due to the medical illness (e.g. Arrhythmia, Angina pectoris, Stroke, Asthma, etc.)
5. More severe pain in regions other than the knee joint.
6. Pregnant
7. When researchers evaluate that it is not appropriate to participate in this clinical test