When taking a photo, such verbal prompts as "cheese" or "smile" are often used by photographers to get natural smiles from their subjects. However, since the obtained smiles usually look forced or resemble a grimace, capturing a natural smile is difficult. We propose an active camera system called "Laughin'Cam" that obtains naturallooking portraits by eliciting spontaneous smiles by presenting the sound of laughter. The proposed system utilizes an emotional contagion effect, which is the tendency of emotional behavior to spread from person to person. We conducted an evaluation experiment with our proposed system using computer vision and also performed a subjective experiment. Our results suggested that our system could efficiently induce naturally-looking and spontaneous smiles.