If your iPhone is restarting for no apparent reason, there are a few things you can do to fix it. Here are a few things you can try to fix a restarting phone.
(1) First, try restarting your phone by holding down the power button and the home button at the same time until the Apple logo appears.
If your iPhone is restarting randomly, you might want to try these tips to fix the issue. Try holding down the Sleep/Wake and Home buttons at the same time for at least ten seconds, until you see the Apple logo. Connect your iPhone to your computer and open iTunes. Select your iPhone in iTunes and select Summary and then Restore.