PURPOSE: To increase the finished extent in the industrial production and reduce the working man-hours in the construction site, by arranging and fixing a ceiling panel in the space provided between building units installed with a specified distance.

CONSTITUTION: First floor building units 2, 3 as under floor building units are placed with a specified distance. The second floor building units 4, 5, 6 are stacked on the first floor building units 2, 3. That is, columns are erected at the four corners and supported by a rigid structure. And a roof unit 7 is stacked on the second floor building units 4, 5, 6. The space between the first floor building units 2, 3. is used for a garage. A ceiling panel 9a provided with a bend at the edge as a unit is arranged at the ceiling of garage 8. That is, the bend at the edge is fixed at hooks 12, 13 previously attached at the upper edges 10, 11 of the opposite sides 2a, 3a of the first floor building units 2, 3.