Application in Tokyo- Myanmar Citizen

I am Myanmar Citizen working in Japan (have working VISA until March 2016). I would like to have a short visit to China less than 2 weeks for having meeting with Vendor. Should I directly apply the VISA to embassy/consulate directly or should I ask my Company's Transvel Agent to apply for me? For my case, regular processing time is 4 working days is still applicable?
Best Regards,
Min