A five-story building in the city of Damanhour, 35 km (85 miles) north of Cairo, caved in due to ongoing demolition work on an adjacent building, state news agency MENA reported.
The initial probe showed the collapsed block was already issued a demolition order that had not been upheld.
The body of a 64-year-old man who was killed in the incident was pulled out from under the rubble.
Two adjacent buildings were evacuated as rescue workers continued to dig through the debris, ensuring no survivors were trapped underneath.
Building collapses are commonplace in Egypt and are often blamed on lax construction, violations of building specifications, and illegal extensions.
Officials often report that dilapidated buildings are issued demolition orders that are not carried out.
Wednesday's accident is at least the third this week.
On Tuesday, four people died and four others were injured when a building crumbled in Egypt's Qalyoubiya governorate after a gas cylinder in one of the apartments exploded.
A day earlier, two people, including a passing police officer, were killed when an apartment building collapsed in the southern city of Assiut, 500km (310 miles) south of Cairo.