To improve safety and attain labor saving and shorter working hours of an assembling work by manufacturing a block so as to be divided into two parts and transferring them, pinchedly holding and hoisting an upper block, suspending down it up to the near position over a lower block transferred directly under it, conforming the connecting metal fittings of the upper and lower blocks into an allowable range so as to abut to each other, and facilitating an engaging metal fitting to be driven into the engaging grooves of both connecting metal fittings or to be screwed into them or to be welded.

An elevating mechanism 60 elevatably suspending an elevator base 50 is provided on a main body frame 70, and a pinchedly holding means 90 capable of pinchedly holding an upper block is suspendingly provided on the elevatable base. Next, directly under the elevator base 50, this assembling device is provided with a traveling carriage 20 capable of transferring the upper and lower blocks, a lateral moving carriage 30 capable of laterally moving on the traveling carriage 20, and a fine adjusting means (transferring mechanism) for conforming upper and lower parts to each other, provided with a turning base 40 capable of turning by a fixed angle.