Does the Nikon d3100 use a SD card, or a Micro SD card?

I'm was about to buy this for it, and thought, I hope it doesn't use micro SD.

http://www.amazon.com/...002TQ6HT6/

It uses an SDHC card - SD high capacity.

The Nikon D3100 is capable of using either straight original old school SD cards, newer SDHC cards, newer still SDXC cards, and in fact CAN use (at least) micro-SD and micro-SDHC cards when mated to the appropriate full size SD card adapter, which the much smaller micro versions of the SD cards simply slide into. Sandisk sells the adapter, (I purchased mine at a local Walgreen's drugstore), it looks just like an SD card shell w/ a small opening made for the much smaller micro-SD card to fit right inside and operate just like a traditional full-size SD, SDHC, or SDXC card. One caveat though, some if not all of the micro-SD cards I've seen can't operate at the fastest read-write speeds that the newest full size SD SDHC and SDXC cards can, so if for example burst shooting or shooting long high-definition videos is important to you, using a slower rated micro-SD card might not be the best idea if you have a choice.

The camera Nikon d3100 uses: SD (Secure Digital), SDHC and SDXC memory cards
http://www.amazon.com/...lias%3Daps

Approved memory cards:
The following SD memory cards have been tested and approved for use in the D3100. Cards with class 6 write speeds are recommended for movie recording. Recording may end unexpectedly when cards with slower write speeds are used.

SanDisk
512 MB、1GB、2GB*1
4GB、8GB、16GB
64GB
Toshiba
512 MB、1GB、2GB*1
4GB、8GB、16GB、32GB
64GB
Panasonic
512 MB、1GB、2GB*1
4GB、6GB、8GB、12GB、16GB、32GB
48GB、64GB
LEXAR MEDIA
512 MB、1GB、2GB*1
4GB、8GB
-
Platinum II
512 MB、1GB、2GB*1
4GB、8GB
-
Professional
512 MB、1GB、2GB*1
4GB、8GB、16GB、32GB
-

*1: Check that any card readers or other devices with which the card will be used support 2 GB cards.

The D 3100 is a real camera, it uses SD and SDHC cards. Only wannabe cams use Micro cards.

Yes it uses SD card so this card would be fine.