An oil supply apparatus includes: an oil pump; a main oil supply path; a sub oil supply path connected to the main oil supply path; a first oil supply section which is connected to the main oil supply path and which supplies oil to a crank bearing section of a specific crank journal; a second oil supply section which is connected to the sub oil supply path and which supplies oil to a crank bearing section of a crank journal other than the specific crank journal; and a control apparatus which sets, as a target oil pressure, a highest required oil pressure among required oil pressures required from a plurality of hydraulic operating sections in accordance with an operation state of the engine, and which controls the discharge amount of the oil pump so that an oil pressure detected by an oil pressure sensor equals the target oil pressure.