To provide an external wall construction structure excelling in external design, weatherability and workability.

The external wall construction structure 1 is constructed by fastening external wall plates 2 to a structure skeleton 10 by fastening metal fittings 5 while carrying out vertical shiplap connection. A cut end 23 of a dimension adjusting external wall plate 20 out of a plurality of external wall plates 2 is fixed to the structure skeleton 10 through an end execution fitting 3. A back plate part 31 of the end execution fitting 3 abuts on a rear side face 26 of the dimension adjusting external wall plate 20, and a front bent part 32 of the end execution fitting 3 abuts on a cut end face 231 of the dimension adjusting external wall plate 20. The back plate part 31 and the rear side face 26 of the dimension adjusting external wall plate 20 are bonded to each other with an adhesive 11. The front bent part 32 of the end execution fitting 3 has a horizontal part 320, a front face part 321 and a third abutting part 322, and a sealing material 163 is disposed in front of the front face part 321.