To provide an attaching structure of an external wall panel, capable of preventing the position shift of the external wall panel when hoisting an external wall, and a manufacturing method of a unit building using it.

On a base part 71 of a stud 7, a plurality of attaching holes 71a are provided. Near the upper side of each attaching hole 71a, a positioning pin 10 is projected. On left and right side parts 811 of a frame 81 of an external wall panel 8, an attaching hole 81a is provided on a part corresponding to the attaching hole 71a of the stud 7. Both of the attaching holes 71a and 81a are formed such that a rivet 9 is to be inserted and fixed. Further, on the left and right side parts 811, a positioning hole 11 is provided on a part corresponding to the positioning pin 10. The positioning hole 11 is formed such that the positioning pin 10 is to be inserted and fitted.