A lever device comprising: a base pedestal; a movable body pivotally supported by the base pedestal to be rotatable about a first lateral shaft; a lever supported by the movable body to be swingable; a cam body having a cam groove, pivotally supported by the movable body to be rotatable about a second lateral shaft and configured to rotate about the second lateral shaft according to swinging of the lever; a guide pin provided on the base pedestal and inserted to the cam groove; and a first biasing member configured to press the cam body in a direction to rotate the cam body about the second lateral shaft, wherein the cam groove includes: an intermediate groove portion curved to be convex in a direction separating from the first lateral shaft; an upper groove portion communicated with an upper end portion of the intermediate groove portion and curved in the direction separating from the first lateral shaft; and a lower groove portion communicated with a lower end portion of the intermediate groove portion and curved in the direction approaching the first lateral shaft, wherein the lever is configured to swing between a push-down position at which the guide pin is arranged in the upper groove portion; and a pull-up position at which the guide pin is arranged in the lower groove portion, wherein the cam groove is provided in the cam body in front of the second lateral shaft, and wherein the first biasing member has: one end connected to a first connector portion provided on the base pedestal; and the other end connected to a second connector portion provided on the cam body, is arranged behind the second lateral shaft when the lever is located at the push-down position, and is arranged in front of the second lateral shaft when the lever is located at the pull-up position. a base pedestal; a movable body pivotally supported by the base pedestal to be rotatable about a first lateral shaft; a lever supported by the movable body to be swingable; a cam body having a cam groove, pivotally supported by the movable body to be rotatable about a second lateral shaft and configured to rotate about the second lateral shaft according to swinging of the lever; a guide pin provided on the base pedestal and inserted to the cam groove; and a first biasing member configured to press the cam body in a direction to rotate the cam body about the second lateral shaft, wherein the cam groove includes: an intermediate groove portion curved to be convex in a direction separating from the first lateral shaft; an upper groove portion communicated with an upper end portion of the intermediate groove portion and curved in the direction separating from the first lateral shaft; and a lower groove portion communicated with a lower end portion of the intermediate groove portion and curved in the direction approaching the first lateral shaft, an intermediate groove portion curved to be convex in a direction separating from the first lateral shaft; an upper groove portion communicated with an upper end portion of the intermediate groove portion and curved in the direction separating from the first lateral shaft; and a lower groove portion communicated with a lower end portion of the intermediate groove portion and curved in the direction approaching the first lateral shaft, wherein the lever is configured to swing between a push-down position at which the guide pin is arranged in the upper groove portion; and a pull-up position at which the guide pin is arranged in the lower groove portion, a push-down position at which the guide pin is arranged in the upper groove portion; and a pull-up position at which the guide pin is arranged in the lower groove portion, wherein the cam groove is provided in the cam body in front of the second lateral shaft, and wherein the first biasing member has: one end connected to a first connector portion provided on the base pedestal; and the other end connected to a second connector portion provided on the cam body, is arranged behind the second lateral shaft when the lever is located at the push-down position, and is arranged in front of the second lateral shaft when the lever is located at the pull-up position.