Inclusion Criteria:

          -  Pathologically confirmed stage IIIB & IV non-small cell lung cancer other than
             squamous cell carcinoma

          -  Patients with one or more measurable lesion based on Response Evaluation Criteria in
             Solid Tumors (RECIST 1.1)

          -  Locally diagnosed sensitive EGFR mutation positive (Exon 19 deletion or L858R)

          -  ECOG performance 0~1

          -  Age ≥ 19 years and - No previous treatment

        Adequate organ function by following:

          -  ANC ≥1,500/uL, hemoglobin ≥9.0g/dL, platelet ≥100,000/uL

          -  Serum bilirubin < 1 x UNL, AST (SGOT) and ALT (SGPT) < 2.5 x UNL, If Liver metastasis,
             Serum bilirubin < 3 x UNL, AST (SGOT) and ALT (SGPT) < 5 x UNL

          -  Serum Cr ≤ 1 x UNL

          -  Patients who have had undergone radiotherapy are acceptable if patients meet all of
             the following criteria:

               -  No history of irradiation to pulmonary tumor lesions.

               -  In case of palliative irradiation to bone lesions in lung: at least 12 weeks must
                  have passed at the date of registration since the last irradiation of the sites.

               -  In case of irradiation to non-pulmonary sites: at least two weeks must have
                  passed at the date of inclusion since the last irradiation of the sites

          -  At the time of registration, at least the following period has passed since last date
             of the prior therapy or procedure:

               -  Surgery(including exploratory/ examination thoracotomy): 4 weeks

               -  Pleural cavity drainage: 1 weeks

               -  Pleurodesis without anti-neoplastic agents (inclusive of BRM such as Picibanil):
                  2 week

               -  Biopsy accompanied by incision (including thoracoscopic biopsy): 2 week

               -  Procedure for trauma (exclusive of patients with unhealed wound): 2 weeks

               -  Transfusion of blood, preparation of hematopoietic factor: 2 week

               -  Puncture and aspiration cytology: 1 week

               -  Other investigational product: 4 weeks

          -  Written informed consent form

        Exclusion Criteria:

          -  Previous history of malignancy within 3 years from study entry except treated
             non-melanomatous skin cancer, uterine cervical cancer in situ, or thyroid cancer

          -  Prior chemotherapy or systemic anti-cancer therapy for metastatic disease but
             postoperative adjuvant or neoadjuvant therapy of 6 months or more previously is
             allowed

          -  Patients who received previous treatment for lung cancer with drugs

          -  Symptomatic or uncontrolled central nervous system (CNS) metastases

          -  Patients with increased risk of bleeding, clinically significant cardiovascular
             diseases, a history of thrombosis or thromboembolism in the 6 months prior to
             treatment, gastrointestinal problems, and neurologic problems

          -  Any significant ophthalmologic abnormality

          -  Pre-existing parenchymal lung disease such as pulmonary fibrosis

          -  Known allergic history of Erlotinib or Bevacizumab

          -  Interstitial lung disease or fibrosis on chest radiogram

          -  Active infection, uncontrolled systemic disease (cardiopulmonary insufficiency, fatal
             arrhythmias, hepatitis)

          -  Pregnant or nursing women