The Shakuntala building, located in Mumbra locality of Thane collapsed around 2:30 am, civic sources said.
Six fire tenders have been rushed to the spot and rescue work is in progress, the sources said.
According to locals 7-8 people are still feared to be trapped under the debris.
The incident comes two months after another building in Mumbra collapsed, killing over 70 persons. The building, Lucky Compound was collapsed in April.