To provide a connection structure of a construction easy in work for tightening a fixing nut firmly and preventing a fixing nut from being loose.

This connection structure of the construction is constituted by burying base ends of anchor bolts into a concrete structure side, making a part of the anchor bolt protrude from the concrete construction, inserting the protruding anchor bolts into tightening holes formed at the construction side to be connected, and screw-fitting the fixing nuts to heads of the anchor bolts protruding from the tightening holes opened at a recessed part formed in the construction to be connected to connect and fix the concrete construction. A sloped washer and a tension member having slopes are arranged between the fixing nut and a bottom wall face of the recessed part by arranging their slopes so as to oppose each other, and a tension bolt screw-fitted into the tension member and arranged vertically with respect to the anchor bolt is operated to connect and fix the construction so that the work for tightening the fixing nut becomes easy and the fixing nut is not easily loosened.