You don’t need to give advance notice at all if you have a valid reason to terminate, as explained here:
If you’re terminating without cause (Art. 15), and it’s not permitted by the contract, you need the employer’s consent. The exception is if you have a non-fixed term contract (which you probably don’t, even if it looks like one) or if you’ve already had the job for three years.
If in doubt, ask a lawyer or the labor department.
Replied in a hurry. Let me clarify:
If LSA Art. 15 applies (which shouldn’t be presumed), the notice period is determined by Art. 16.
If you use Art. 14, there’s no minimum notice period.
If you use Art. 15, and the work period is less than 3 months, there’s no minimum notice period.
Again, make sure you’re terminating the contract properly. They should give you a letter saying you no longer work for them (離職證明書 or 服務證明書). The safe way to terminate is to use a legal deposit letter, but an email should suffice. If the termination is proper, but they don’t give you the letter, they can get in trouble for violating LSA Art. 19.