COVID-19 is a pathogen called SARS-CoV-2, an RNA virus that can infect various animals, including humans. As COVID-19 spread globally, the World Health Organization upgraded it to a pandemic in March 2020. In addition to solving the problem of shortage of medical personnel, rapid and accurate classification of infected patients emerged as an important issue. Therefore, we propose a deep learning-based chest X-ray image reading model that can notify the doctor whether the patient is infected. The goal is to achieve multiclass classification, which not only classifies COVID-19 infections, but also other lung diseases to help the medical community. The proposed method is a combination model. It involves pre-processing the chest X-ray image using the image augmentation method and various convolutional neural network (CNN) models. The purpose of the proposed method is to classify COVID-19, normal people, and viral pneumonia appropriately. Overall, 15,153 X-ray images were used in the study. By using the proposed method, we obtained a model with high accuracy through improved image data. Characteristically, some models tend to detect COVID-19 and pneumonia properly. Finally, an ensemble model was created using models made by the proposed method. Eventually, we obtained a high accuracy ...