You can purchase Niconico Points by following these steps:
Log into the account you wish to purchase Niconico Points on
Navigate to Niconico Point page
Click on “ポイントを購入する”(Purchase Points)
Select your payment method by clicking “お支払い方法を選択してください”(Select Payment Method)
This step is only required when you purchase for the first time.
To change your payment, select "変更"
Select how many points you need from the list *Points are not offered by a single unit
Follow the instructions listed on the screen
There will be a purchase confirmation screen.
Once you confirm your purchase then click on “購入”(Purchase)
If your purchase has gone through successfully, you will see a confirmation right away.
Go to your My Page to see how many points you have. If you can’t see your points in your My Page, please try logging out of Niconico, and log back in and see if the correct balance is reflected.