To provide a unit building having a shelter structure with excellent habitability and economic efficiency.

The lower story building unit 21B of this unit building 11 comprises a plurality of general building units 22A and a high strength unit 22B having a holding strength higher than that of these general building units 22A. The general building units 22A and the high strength unit 22B are connected to each other with docking plates 31 fitted to columns 23, 25 adjacent thereto. Specifically, the docking plate 31 comprises an insertion hole part 31a and a pin 31b. The docking plate 31 is installed while the stacking pin 35 projecting upward from the upper surface part of each of the columns 23, 25 is inserted into the insertion hole part 31a, and the pin 31b is inserted into the hole part 36 of each of the columns 23, 25. The breaking load of the stacking pin 35 is set within the breakage design load of a unit connection portion.