"mruby", a programming language from Fukuoka, is lightweight so that it can be applied to embedded development while maintaining the high development efficiency of Ruby. Since it can be programmed with about 1/4 the amount of code compared to C language, it has characteristics such as memory saving and low power consumption, and in recent years it has been attracting attention for its high affinity for the "IoT" field. In this lecture, we will introduce the products and introduction examples of companies that utilize mruby and mruby / c. We look forward to your visit if you are interested in highly productive embedded development and IoT related services.