Mich. Comp. Laws § 47.15

Sec. 15. Before entering upon his official duties each member of the board of county auditors shall execute a bond in the sum of 2,000 dollars with sufficient sureties to be approved by the circuit judge of said county, assuring the faithful performance of his respective duties, and shall take and subscribe to the constitutional oath of office and file the same in the office of the county clerk. The expense of procuring the said bonds shall be paid by the county.