PURPOSE: To enhance the easiness in executing works by feeding a plurality of main bars paid off from a bobbin into a pile hole under guidance, and coupling hoop bars around them upon locating one by one.

CONSTITUTION: A plurality of main bars 2 paid off from a bobbin 4 are held in the specified positions at the bore of a pile hole P using a guide means 5 and fed into the hole P intermittently by a transport means 6. When the main bars 2 are at a standstill, hoop bars 3 are positioned by a hoop bar holding means 7 around the main bars 2 in such an arrangement as intersecting perpendicularly, and the two groups of bars are coupled together. Therein the hoop bars 3 retained in a stack by a storing device 27 are separated by a separating device 28 and aligned with the main bars 2. A preceding plate 12 whereto the tip of each main bar 2 is secured, is intermittently transported by a transport means 15 together with an operational rod 14, and thereby the main bars 2 can be drawn into the hole P while they are held in place accurately. After laying of a cage-shaped reinforcement. concrete is placed in the hole P. This permits executing the works accurately without requiring a space for erection of reinforcement and use of any crane.