A number of houses were evacuated after the device was discovered on Ainsworth Avenue off the Shankill Road.
The security alert has now ended.
Police have appealed for information about the incident.
Democratic Unionist Party MLA William Humphrey said those behind the device had been "utterly reckless".
"This criminal act of madness will be condemned by all right-thinking people," he added.
Police have said a suspicious object found in west Belfast was a "crude but viable" bomb.