Hello, Kitano Yuri san,
This "々" is not kanji.
It is kind of mark which mean repeating the ajacent kanji.
So it doesn't have its own on-yomi and kun-yomi.
We call it "おどり字(odoriji)", "送り字(okuriji)" or "繰り返し符号(kurikaeshi fugou/repeating mark(?))"
In a computer dictionary, it is often recorded as "おなじ(onaji)".
If you use MS-IME2000, you can convert from "ONAJI".
Cheers.