In an automated bobbin-exchanger device (3), a guide groove (6) which is provided on a vertical transfer base (5) has a horizontal portion (6a), a vertical portion (6c) and an arcuate portion (6b). A bobbin chuck (18) reciprocally moves pivotably along the guide groove (6) to make a travel distance minimum, thus enabling users to quickly exchange the bobbin case (12). By placing a bobbin holder (13a), a chuck-drive lever (14) and a chuck-drive air-cylinder (26) circumferentially, it is possible to make a whole structure compact and space-saving. The bobbin-exchanger device (3) requires only two bobbin cases (12) available to make their check and maintenance easy.