Provided is a hydraulic oil composition containing a base oil (A), an antioxidant (B) including an amine antioxidant (B1) and a phenolic antioxidant (B2), and a succinic acid imide compound (C), wherein the hydraulic oil composition satisfies requirement (I), and is used in a hydraulic device that includes a wet brake and/or a wet clutch, that has a working pressure of 30 MPa or more, and that is selected from construction machines, general industrial machines, and power generators. The hydraulic oil composition provides excellent wear resistance and an excellent effect of inhibiting the occurrence of sludge, and excellent braking performance and clutching performance even when the hydraulic device is used under high-pressure conditions. Requirement (I): the static friction coefficient (μs) after 1000 cycles is 0.100-0.162 as measured in accordance with SAE No.2 test described in JCMAS P 047: 2004.