Definitely, just like in India we get almost all the dairy products including Milk in Japan as well.
You will be able to find a wide variety of butter, cheese, yogurts and ice creams but, if you're lo...oking to buy specifically Paneer, Khoya, Ghee or any other authentic Indian dairy products then it would be a little difficult to find in a nearby Japanese supermarket. Eventually, you will have to go to an Indian Store where you can find frozen Paneer, Ghee and most of the Indian spices. Though, prices are a little bit higher than what we pay in India. I will give you a rough estimate for some of the dairy products which are used in everyday basis.
Milk: 200~300YEN (120~200INR) for 1L Carton
Plain Yogurt: 120~160YEN (75~110INR) for 400~500gm
Paneer: 1200~1400YEN (800~1000INR) for 1kg diced cubes (Brand: Amul, Nanak)
Indian stores are very few in number but if you are in Tokyo then areas like (Nishi-kasai, Funabori, Shin Okubo, Ikebukuro) you will be easily able to find them.
I hope this was helpful!
Tushar