In this talk, we introduce Optuna, a next-generation hyperparameter optimization framework with new design-criteria: (1) define-by-run API that allows users to concisely construct dynamic, nested, or conditional search spaces, (2) efficient implementation of both sampling and early stopping strategies, and (3) easy-to-setup, versatile architecture that can be deployed for various purposes, ranging from scalable distributed computing to lightweight experiment conducted in a local laptop machine. Our software is available under the MIT license (https://github.com/pfnet/optuna/). Takuya Akiba, Shotaro Sano, Toshihiko Yanase, Takeru Ohta and Masanori Koyama