I found a part of an old MIDI Drum Kit, even perhaps soviet drum (I'm from Russia). It hasn't any controller inside, only MIDI out and cables conected with magnet. I need an advise how can I convert it's, perhaps, electric signals to MIDI.
Well we need a lot more information than that to help.
You need to get it powered up and see what comes out, with a scope, when you hit the pads.
Which scope i shoud use?
Any one you have, the signals are not very high frequency.
You do know what a scope is?
Not at all, I'm novice.
Well I am afraid that it is a piece of test equipment that might cost you a lot of money
However without one you will struggle to do any electronics.
You can make one with a laptop and an arduino. Just google arduino oscilloscope, for lots of designs.
These will let you see signals coming out of your pad. Unfortunately for you because this is so obscure unless you can get data on it you have to investigate and it is not the sort of thing a beginner is capable of doing. Spend a year doing electronics and stuff and then come back to your project.
Yeah. This is exactly that I was affraid. 
Thanks for help.