This paper proposes a novel inerter-based electromagnetic device and investigates its performance as a vehicle suspension strut. The inerter-based electromagnetic device is obtained by placing the flywheel employed in an existing inerter prototype into a constant magnetic field. During rotation of the flywheel, the flywheel is doing the magnetic line cutting motion, which makes the flywheel perform as a Faraday generator. The influences of different types of loads on the behaviour of the inerter-based electromagnetic device are analyzed, and it is shown that the resistive, capacitive and inductive loads can contribute to the damping, the inertance, and the stiffness of the whole device, respectively. Moreover, the proposed device can also be used to realize higher-order mechanical admittances by using electrical circuits. The performance of the device as a suspension strut is also studied. Numerical simulations show that the proposed device can not only provide improvements on the suspension performance (ride comfort and road holding) compared with the conventional strut, but also generate an amount of electric energy that can be utilized by other parts of the vehicle.