Firefighters were called to the blaze in Defford Drive, Oldbury, at around 1.20pm on Tuesday after reports of "smoke and flames".
Crews from Oldbury, Haden Cross, Handsworth and Smethwick attended the incident, with the first crew arriving in under four minutes.
A man in his 70s was confirmed dead at the scene, with West Midlands Police supporting the man's family and the current investigation.
A spokesman for West Midlands Fire Service said: "Fire investigation officers remain at the property and investigations continue into the cause of the incident."
