I got beacon which use nRF51822.
I need to get radiated pattern diagram as attached picture.
this is to get KC certificate.
How can I get information? beacon maker don't know about these information.
I think I should ask manufacturer of chip so I ask here
well no you need to ask the beacon maker and if they don't have it - find a better beacon maker which does have this information. Nordic ONLY makes the IC, the radiation pattern has nothing at all to do with the IC, it has everything to do with the antenna used, how it's mounted, how it's tuned, the thickness of the board it's on, the enclosure it's in etc. That is all specified by the beacon manufacturer.
Alternatively find a testing lab and take your device there and have them measure it. This is something any reputable device manufacturer should have done which makes it rather seem you might want to look for a better one.
Thank you for your kind reply :) I should find another manufacturer or take alternative way that you mentioned.