A dental treatment device in which attenuation of a laser beam is not liable to occur is provided. This dental treatment device is provided with a vibration unit for vibrating by a vibrator that generates ultrasonic vibrations, a chip unit connected to the vibration unit and through which ultrasonic vibrations are transmitted, a flow channel for discharging an antimicrobial agent from the chip unit, and an optical system for irradiating a laser beam for photo-decomposing the antimicrobial agent from the chip unit, the optical system having an optical path separate from the flow channel.
