The Regulations Governing Labor by Prisoners Article 21

The prisoner’s external work shall be limited to the collaborated working unit designated by the prison.The prisoner engaged in external work may, with the consent of the prison, be assisted with relevant insurance matters by the collaborated working unit.
中文原文 受刑人作業實施辦法第21條
受刑人從事監外作業,以監獄指定之作業協力單位者為限。
從事監外作業之受刑人,得在監獄同意下,由作業協力單位協助投保相關保險。

English translation for reference only; the Chinese text prevails. Not legal advice.