Hello Mr Y.
If you are performing a logical dump and load, you can go direct from 5.5 to 5.7, otherwise for InnoDB/MyISAM tables, conventional wisdom is to first upgrade to the most recent version on your current series, then upgrade through each major release, i.e. 5.5 to 5.6 then 5.6 to 5.7. There has been a little testing done on direct 5.5 to 5.7 but as far as I know, it is not officially supported by Oracle.
Also be aware that 5.7 changes many behaviors quite significantly and as such there is a very good chance that your application may not function as expected out of the box so you should test with a staging instance first.
George O. Lorch III
Software Engineer, Percona