Cancer is an uncontrolled and destructive proliferation of body cells. Lung cancer is the highest cause of death in Indonesia, especially among men. The cancer patient can be examined for histopathological checkups. This examination is carried out by taking body tissue at a place where cancer cells are suspected. Histopathology is the gold standard for detecting pathology or abnormalities in body cells. The results of a histopathological examination can differentiate between normal body cells, cancer cells, and their types. There are three types of lung cancer histopathology: adenocarcinomas, squamous cell carcinomas, and benign lung tissues. Classification of lung cancer using histopathology images is an alternative to detecting the severity of cancer. This study used Deep Learning Convolutional Neural Network (CNN). Transfer learning utilizes ImageNet weights and biases from the Inception-v3 pre-trained network, so a new model is not trained from scratch. The hyperparameter uses a learning rate (LR) of 0.0001, epoch 50, batch-size 32, and RMSProp optimization. In addition, there is tuning with reduced lr when there is an increase in validation loss before reaching the maximum epoch. The dataset uses the LC25000. The data consists of 3,000 images, three classes with 1,000 classes per class. The best results show accuracy, precision, and recall are 99.17%, 99.17%, and 99%, respectively. Performance increased by 3% compared to the baseline method without learning rate tuning.