Eating disorders are characterized by uncontrolled eating behaviors. The core psychopathology is expressed in a variety of ways: body image distortion, preoccupation with food and weight, fear of weight gain, and so on. Brain-imaging techniques provide many opportunities to study neural circuits related symptoms in eating disorder. The present article focuses studies about functional magnetic resonance imaging (fMRI) of eating disorders. Studies of anorexia nervosa suggest 1) relationship between amygdala activation and fear of weight gain, 2) relationship between prefrontal cortex activity and cognitive flexibility. Studies of bulimic eating disorder (bulimia nervosa, binge eating disorder, and so on) suggest 1) relationship between brain reward system and overeating, 2) relationship between prefrontal cortex activity and impulse control.