STATE QUANTITY CALCULATION DEVICE, CONTROL DEVICE, AND VEHICLE

Realized is a technique of highly accurately calculating a state quantity of a vehicle. An ECU () of a vehicle () includes a ground contact load calculating section (), an input quantity calculating section (), a first state quantity calculating section (), an observable calculating section (), a second state quantity calculating section (), and a damper ECU (). The ECU () calculates a first state quantity of the vehicle () by inputting, into a vehicle model, a value calculated from a G sensor value and/or the like, and calculates a second state quantity of the vehicle () by correcting the first state quantity with use of an observable which is calculated from a ground contact load and a spring constant gain of a tire.