To dispense with provision of a high structure type supporing tower supporting a spud so as to be elevatable by disposing a guide for guiding the spud elevationwise below a deck of a working boart, and providing a spud elevation driving boosting mechanism for elevationwise driving the spud along the guide.

A spud device for a woring board 2 is composed of a guide for elevationwise guiding a spud 3 in the vertical direction, and a sud elevation boosting mechanism 5 for elevation driving the spud 3 along the guide 4. The mechanism 5 has a first running block 51 and a second running block mounted at both sides of the spud 3 and also has first - fourth fixed blocks 53, 54... and an auxiliary fixed block mounted at an upper circumferential edge of the guide 4. A wire rop 59 is wound around these blocks by a winding up device 58. With the constitution, the purpose is attained.