Somali Police Force said in a statement the attacker clad in a suicide jacket blew up at the cafe located near a police station in Shangani district at about 7pm local time.
The cafe is popular and frequented by residents for evening pastime. Four other people were injured according to the police.
The attack happened barely eight hours after Somali military said it killed 76 Al-Shabaab militants in Lower Shabelle region following a morning ambush.
According to a military statement, Al-Shabaab fighters attacked Barire and Awdegle forward operating bases in the wee hours of Saturday.
Somali National Army added that it captured ten militants alive.
But in a swift rejoinder, Al-Shabaab claimed that it killed 46 soldiers and seized weapons and vehicles.
There was no immediate claim of responsibility for the Shangani bombing.