An oil strainer is arranged between an oil pan configured to close a lower opening of a transmission case and a control valve body which is installed in the lower opening. The control valve body has a discharge hole of oil in a portion opposing the oil strainer. The oil strainer has an oil suction port in a portion opposing the oil pan, and has a rib projecting on the control valve body side on a surface of a portion opposing the control valve body. When seen from the oil pan side, the oil suction port and the discharge hole are provided so that positions are not matched from each other. When seen from the oil pan side, the rib is provided to cross a straight line passing through the oil suction port and the discharge hole in a region between the oil suction port and the discharge hole.