PURPOSE: To provide a ceiling simple in ceiling panel connecting and disconnecting work by providing engagement parts on framed main joist and sub-joist edge, fitting the ceiling panel at a part surrounded by the main joist and the sub-joist and elastically engaging an engagement spring projected on the back surface with the engagement parts.

CONSTITUTION: A main joist 1 and a sub-joist 2 are framed in lattice-work, and engagement parts 3 are provided on the main joist 1 and the sub-joist 2. A ceiling panel 4 is fitted in a space part surrounded by the main joist 1 and the sub-joist 2, and an engagement spring 5 projected to the back surface side of the ceiling panel 4 is elastically engaged with the engagement part 3. Consequently, installing work of the ceiling panel 4 is simplified, and the optional ceiling panel 4 can be connected and disconnected, and accordingly, inspection work of an attic is facilitated.