Projector

A liquid-cooling device configured to cool down an optical element in a projector using cooling liquid, comprising:

• an optical element holding member that is constructed to allow cooling liquid to flow in and out and holds the optical element so as to transfer heat to the cooling liquid;
• a liquid pumping unit configured to circulate cooling liquid;
• a liquid storage unit that is constructed to allow cooling liquid to flow in and out and temporarily stores cooling liquid therein;
• and
• a plurality of liquid circulation members configured to connect the optical element holding member, the liquid pumping unit, and the liquid storage unit and define a flow channel of the cooling liquid, and
• the liquid pumping unit, the liquid storage unit, and the optical element holding member are arranged along a circulation direction of the cooling liquid along the flow channel in order of the liquid pumping unit, the liquid storage unit, and the optical element holding member.