A juice extractor is adapted to squeeze juice from oranges and similar kinds of fruits. The juice extractor includes a juice extractor base and a juice squeezing wheel rotatably disposed on the juice extractor base. An arcuate concave surface is formed on an upper portion of the juice extractor base. The juice squeezing wheel has an involute outer surface. A crushing space is defined between the juice squeezing wheel and the concave surface of the juice extractor base for receiving a half-cut fruit. When the juice squeezing wheel rotates, the half-cut fruit in the crushing space is crushed to produce fruit juice. The juice extractor can squeeze juice electrically, is structurally simple and is convenient to be washed.