<p>A monitor is provided to enable a user to adjust a horizontal state of the monitor precisely without any equipment during installation of the monitor by installing a horizontal state checking unit for checking the horizontal state of the monitor promptly to the monitor. A stand(11) supports a monitor body(10) and permits movement to the monitor body. The horizontal state checking unit(20) is installed to a central part of an upper side of the monitor body and checks the horizontal state of the monitor. The horizontal state checking unit includes an indicating bar keeping a perpendicular state always by a weight attached to a lower end and a scale indicating part indicating scales attached to the monitor body. The horizontal state checking unit is a leveler filling the inside of a scaled glass tube with liquid and including an air bubble. The scales indicate a horizontal allowance of the monitor body.</p>
