At present, the pachinko slot gaming population is 9 million, and the market size is calculated to be 19,540 billion yen. It is a very large market, and it is hoped that users and companies will develop with reduced overhead. Online pachinko that uses smart contracts  is characterized by being able to play at home. In this research, we propose an online pachinko system using smart contracts. There are many games that use smart contracts and block chains. However, to the best of the author's knowledge, none of the current pachinko slots incorporate the concept of settings that determine the winning percentage of users. This is because it is not possible to hide the parameter that determines the winning rate because all users can confirm the transaction details, which is a feature of blockchain. In this proposal, we propose a method for concealing the settings and security against fraud of users and companies and attacks against various smart contracts. We also implement the proposed online pachinko system and clarify its efficiency.