Korean, now temporary stay in Japan, want to apply china visa

i am Korean works for China Local city R&D Center as Chief, made by local government and private company together.
4days ago I arrive from Harbin China to Tokyo for attending 10th Battery Japan of International secondary battery exhibition.
When I try to return Harbin then I catch the big trouble, my visa is expired and only I have stay extension permit within China territory.
So now I cannot return China Harbin.
Can I apply China in entry permit Tokyo, still I stay in Saitama.