This study aims to clarify the development of online learning practice of engineering education in a Japanese university under the pandemic of the COVID-19. The research question is how online learning, especially blended learning, was practiced. By 2020, advances in Internet technology and its widespread use had already formed the basis for online classes. However, face-to-face classes were the mainstream, and there were few online classes for undergraduate education. We will present the development of online learning at a Japanese university, which is a private technical university in the bay area of Tokyo, Japan, as an example. This university had conducted all classes online in the first semester of 2020. The transition to online classes was unexpected, and classes started in May, a month late. In the second semester, some classes were face-to-face, while many classes were online. We will present: 1. how progressed the teaching style to blended learning, 2. how changed the students’ understanding of classes, 3. how changed the students’ satisfaction level of classes. The significant difference is that blended learning started in the second semester. The understanding and satisfaction of the students have improved in the second semester. The background of this development is also that the faculty, administrators, and students collaborated to work on education innovation.