A composite operating device comprising: an operating member that is operable to rotate about a specific axis of rotation and operable to slide in a direction orthogonal to the axis of rotation; a slider that rotatably retains the operating member and slides in the same direction as a sliding direction of the operating member in conjunction with a sliding operation of the operating member; and a base that retains the slider so as to allow the slider to slide in the sliding direction, wherein one of the base and the slider comprises a flexible portion that is capable of elastic bending deformation in a predetermined direction relative to the other, the flexible portion comprising a first engagement portion that engages with the other of the base and the slider, the other of the base and the slider comprises a second engagement portion that engages with the first engagement portion in a state in which no operating force in the sliding direction is applied to the operating member, thereby retaining the slider in a neutral position in which the slider is not displaced in the sliding direction, the second engagement portion being shaped such that when an operating force in the sliding direction is applied to the operating member, the second engagement portion presses against the first engagement portion while being displaced in the sliding direction relative to the first engagement portion, thereby causing bending deformation of the flexible portion, and the first engagement portion and the second engagement portion are shaped such that an amount of deformation of the flexible portion increases with an amount of operation of the operating member in the sliding direction, characterized in that two slits are formed in the flexible portion such that the flexible portion can be deformed in a direction parallel to the axis of rotation. an operating member that is operable to rotate about a specific axis of rotation and operable to slide in a direction orthogonal to the axis of rotation; a slider that rotatably retains the operating member and slides in the same direction as a sliding direction of the operating member in conjunction with a sliding operation of the operating member; and a base that retains the slider so as to allow the slider to slide in the sliding direction, wherein one of the base and the slider comprises a flexible portion that is capable of elastic bending deformation in a predetermined direction relative to the other, the flexible portion comprising a first engagement portion that engages with the other of the base and the slider, the other of the base and the slider comprises a second engagement portion that engages with the first engagement portion in a state in which no operating force in the sliding direction is applied to the operating member, thereby retaining the slider in a neutral position in which the slider is not displaced in the sliding direction, the second engagement portion being shaped such that when an operating force in the sliding direction is applied to the operating member, the second engagement portion presses against the first engagement portion while being displaced in the sliding direction relative to the first engagement portion, thereby causing bending deformation of the flexible portion, and the first engagement portion and the second engagement portion are shaped such that an amount of deformation of the flexible portion increases with an amount of operation of the operating member in the sliding direction, characterized in that two slits are formed in the flexible portion such that the flexible portion can be deformed in a direction parallel to the axis of rotation.