Visa Information
Visitors to Taiwan must obtain a visa or authorization in advance, unless they come from one of the visa exempt countries or countries whose nationals are eligible for visa on arrival. All visitors must hold a passport valid for 6 months (except the citizens of Japan who can hold a passport valid for 3 months, and citizens of United States who are only required to hold a passport valid for the entire duration of stay).

Useful link
https://www.immigration.gov.tw/5475 (English version)