Yes, It Is a Radish
Googling for pictures of radishes, I saw that they were spherical and perhaps an inch or two in diameter, contrasting with the image, as some posters noted. But further searching for different varieties of radish turned up a winter radish, called the "China Rose", which has a somewhat longer planting cycle than some other varieties, and corresponds roughly to the image.
Closely related to this Chinese variety of radish is a Korean variety, the Diakon, which is known to the Japanese as the Kowari radish (a Kowari is a small furry animal, though, so don't just ask for a Kowari). This could be what we're seeing in the photograph, but images I have seen of that variety of radish show it as having a white color, and being slimmer than those in the picture.
So presumably, they grow more than one kind of radish in North Korea, and these are China Rose radishes that he is inspecting: this variety is even grown in the United States.
The Italian Candle of Fire radish looks a bit like this kind of radish as well: although it's considerably slimmer, at least it's the right color.