The device has a 4.3in (10.9cm) screen, which is slightly bigger than its predecessor, the S3 Mini.
The company will show off the smartphone at an event next month, but has not yet given a date for when it will go on sale.
The 5in (12.5cm) S4 phone launched in April, and according to Samsung has sold more than 10 million units.
The mini version, the specifications of which were leaked online earlier this week, will need to convince consumers that it is not simply an underpowered phone sold with the help of Samsung‘s “premium” Galaxy brand.
Last year, the company released the S3 Mini, which was criticised at the time for being much less powerful than its bigger sibling.
“Those hoping Samsung‘s Galaxy S3 Mini was simply a smaller version of the company’s flagship phone may be disappointed,” wrote technology news site GigaOM at the time of the S3 Mini’s release. “This is for the budget market.”
Another site, knowyourmobile.com, said: “Given the competition, [it’s] way too expensive for what’s on offer.”
The S4 Mini has an eight-megapixel camera on its rear, compared with the S4’s 13 megapixels. The Mini’s 1.7GHz dual core processor is also less powerful than the quad-core chip found in the larger model.
But such hardware downgrades were understandable, said Nick Dillion, mobile analyst for Ovum.
“The point of it is to offer some of the bits of flagship device to a user who isn’t quite as demanding and doesn’t want the latest features and spec.