To provide a light irradiator using a visible red light emission diode easily transmitting infant body tissue for use in a medical field.

In this visible red light emission diode irradiator, the red light emission diode with its irradiation direction fixed upward is mounted to the tip part of an arm part extended from the side face of a case enclosing an electronic circuit and a battery, and rated electric power determined by the electronic circuit is supplied from the battery to allow the red light emission diode to emit light. The red light emission diode is covered with a cover using a cushion member with a specified circular hole opened in the center part.