A lens apparatus includes a base member including a rectilinear guide groove portion, a cam barrel including a cam groove portion, a lens holding member provided with a roller member inserted into the rectilinear guide groove portion and the cam groove portion and configured to support a lens unit, a first light amount adjustment unit, a biasing member configured to bias the roller member to the cam groove portion, and a pressing member provided between the first light amount adjustment unit and the lens holding member and configured to press the biasing member, wherein the first light amount adjustment unit includes a rotation regulating portion configured to regulate rotation of the pressing member around an optical axis of the lens unit.