The man, 34, who is originally from Devon, was arrested on suspicion of child abduction and kidnap during a raid on a property where missing schoolgirl Leona Peach was found.
Leona, who is said to have been discovered safe and well, is now being supported by specialist officers and child services.
She had been reported missing from Newton Abbot in Devon on December 20, having last been seen in the Hele Park area.
Police began looking for her after she was believed to have left home to be with her father.
The man is now being transferred to the Devon and Cornwall Police area for questioning.
In a statement, the force said: “Officers would like to thank the public for their support in helping us locate Ms Peach.”