Travelling to Taiwan from China and re-entering.

I am working in China this summer. At the end of my work time, I plan on visiting a family member in Taiwan, leaving China from Hangzhou and returning back to Hangzhou from Taiwan (after 5 days) for my return flight to the UK. Will I need a multiple entry visa to take this trip, even though coming back from Taiwan I won't be leaving Hangzhou airport? Many thanks, Peter.