National Pension Act Article 32

The insured persons, once qualified for the Insurance and the old age benefit of the labor insurance, are entitled to apply for insurance payments to any one of the insurers at the same time. The insurer accepting the application shall calculate the payments based on respective insurance periods. Payments calculated respectively will then be combined and paid to the applicant according to the rules. Payments to be shared by other insurers shall be repaid by the respective insurer.Under the circumstances that the insurance period from the previous paragraph does not meet the limits of applying for old age pension payments but qualifies for such application if calculated in combination with other insurance periods, the applicants are still entitled to apply for old age pension payments. The insured persons under Article 7, Subparagraph 1 and Subparagraph 3, are forbidden to choose payment methods stipulated in Article 30, Paragraph 1, Subparagraph 1 when applying for the old age pension payment of the Insurance if they have already received senior pension payments from other insurances.Rules of the granting of combined old age pension payments, the repayments of respective shares among insurers, and other related affairs as stipulated in Paragraph 1 shall be drawn jointly by the central competent authority and the central competent authority of labor insurance.
中文原文 國民年金法第32條
被保險人符合本保險及勞工保險老年給付請領資格者,得向任一保險人同時請領,並由受請求之保險人按其各該保險之年資,依規定分別計算後合併發給;屬他保險應負擔之部分,由其保險人撥還。
前項被保險人於各該保險之年資,未達請領老年年金給付之年限條件,而併計他保險之年資後已符合者,亦得請領老年年金給付;其為第七條第一款及第三款之被保險人者,如已領取他保險老年年金給付,於本保險之老年年金給付,不得選擇第三十條第一項第一款之給付方式。
第一項老年給付之合併發給、保險人間應負擔部分之撥還及其他相關事項之辦法,由中央主管機關會同勞工保險中央主管機關定之。

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