A cover-equipped manual valve having a ratchet mechanism for preventing rotation of a knob, comprising: a rod formed with an external thread portion on an outer periphery thereof, the rod being unconnected to the knob and held against rotation; a sliding nut of a cylindrical shape, the sliding nut being rotatably held by a body and internally formed with an internal thread portion threadedly engaged with the external thread portion of the rod; an engagement member fixed to the knob, the engagement member being elastically deformable to be engaged with the sliding nut and to be disengaged from the sliding nut when larger torque than a predetermined value is applied to the engagement member; and a knob cover of a hollow shape for covering the knob.