Since no one answered my question so I've tried to search it on my own. I took out the gearbox dipstick and following was written on it:
Notice: No need to replace ATF under normal driving condition. See owner's manual when replacing.
Another mark on dipstick:- TYPE T IV
So guys it's NOT CVT oil in my Fielder but Toyota T IV. I recently bought CVT oil for my brother's Vitz and it's written:
Use the fluid only for the vehicle indicated
"Toyota Genuine CVT Fluid TC"
Should the fluid be used for other vehicles, it will cause damages.
It means that you MUST NOT make a costly mistake of changing your Fielder's transmission fluid (if it's T IV) with CVT just by hearing its necessity from someone.