Hampshire Fire and Rescue Service was called to the incident at 15:22 on Tuesday 5 November.
The incident was at a domestic property in Whiteshute Lane, Winchester.
The man was pronounced dead at the scene by South Central Ambulance Service.
Crews from Winchester and Eastleigh attended the incident in the first-floor flat.
Hampshire Constabulary and South Central Ambulance Service also attended the scene.
The fire was extinguished using two breathing apparatus’, one hose reel jet, and one main jet.
An investigation by Hampshire Constabulary is being conducted to establish the cause.