The blast took place at the building's sixth floor in the early hours after which fire broke out in that area.
Ten people were injured, three of them seriously, state-run Xinhua news agency reported.
While one person was confirmed dead, search is on for four missing people in the rubble.
The accident has caused damages from the ground floor to the seventh floor of the building, witnesses said.
The search and rescue work is continuing at the building located in Weihai Economic and Technology Development Zone.
Preliminary investigation indicated the blast was caused by a gas leak, the report said.