To provide a new cyclic siloxane compound useful for an Si-containing film-forming material, especially for a material for a low dielectric constant insulating film suitable for a PECVD (plasma enhanced chemical vapor deposition) equipment.

The present invention provides a cyclic siloxane compound represented by general formula (20) where R18 represents a hydrocarbon group, R19 represents a hydrogen atom or a hydrocarbon group, g represents an integer of 2 to 10, and h represents an integer of 1 to 3. A specific example of the cyclic siloxane compound includes 2,4,6-tris(methoxymethyl)-2,4,6-trimethylcyclotrisiloxane.