Cosmetic oil thickener and oil-soluble copolymer

A cosmetic containing an oil thickener, and at least one oil which is selected from the group consisting of a hydrocarbon oil, an ester oil, and a higher alcohol, wherein

• the oil thickener is an oil-soluble copolymer having a monomer unit composed of a hydrophilic monomer, a monomer unit composed of an easily-crystallizing hydrophobic monomer, and a monomer unit composed of a poorly-crystallizing hydrophobic monomer,
• the oil-soluble copolymer contains the monomer unit of the hydrophilic monomer in a range of 30 to 50 mol %, contains the monomer unit of the easily-crystallizing hydrophobic monomer in a range of 40 to 65 mol % and contains the monomer unit of the poorly-crystallizing hydrophobic monomer in a range of 5 to 15 mol %,
• the amount of the oil thickener is 3 mass % or greater, in 100 mass % of the mixture of the oil thickener and the oil,
• the cosmetic exhibits a static viscosity of between 100 Pas and 20,000 Pas under conditions of a shear rate of 0.0001 s−1 and 25° C. atmosphere.