A construction machine, comprising: a main pump; a swing motor operated by receiving a hydraulic oil from the main pump; an operation unit configured to control a rotation direction and a rotation speed of the swing motor; a swing valve configured to control flow of the hydraulic oil by the main pump to supply the hydraulic oil to the swing motor and to control the flow rate of the hydraulic oil discharged from the swing motor toward a tank according to the operation amount of the operation unit; a hydraulic oil control valve unit provided between the swing motor and the swing valve and configured to control the flow of the hydraulic oil according to a pressure of the hydraulic oil at opposite ends; a first accumulator configured to store the hydraulic oil having passed through the hydraulic oil control valve unit when the swing motor is decelerated; a regeneration control valve provided between the hydraulic oil control valve unit and the first accumulator; a first pressure detection member provided between the swing motor and the swing valve and configured to detect a pressure of the hydraulic oil flowing into the swing motor; a second pressure detection member configured to detect a pressure discharged from the swing motor; and a controller configured to control the hydraulic oil control valve unit and the regeneration control valve by determining acceleration, deceleration or deceleration reverse lever of the swing motor according to a signal of the operation unit and a difference between the pressure detected by the first pressure detection member and the second pressure detection member, wherein the controller is configured to determine that the swing motor is in an acceleration state, in case where the rotation direction of the swing motor is selected to a first direction by the signal of the operation unit, if the pressure detected by the first pressure detection member is higher than the pressure detected by the second pressure detection member, to determine that the swing motor is in an deceleration state, in case where the rotation direction of the swing motor is selected to the first direction by the signal of the operation unit, if the pressure detected by the second pressure detecting member is higher than the pressure detected by the first pressure detecting member, and to determine that the swing motor is in deceleration reverse lever state, in case where the rotation direction of the swing motor is the first direction but the current rotation direction of the swing motor is selected to the opposite direction to the first direction by the signal of the operation unit, if the pressure detected by the second pressure detection member is higher than the pressure detected by the first pressure detection member. a main pump; a swing motor operated by receiving a hydraulic oil from the main pump; an operation unit configured to control a rotation direction and a rotation speed of the swing motor; a swing valve configured to control flow of the hydraulic oil by the main pump to supply the hydraulic oil to the swing motor and to control the flow rate of the hydraulic oil discharged from the swing motor toward a tank according to the operation amount of the operation unit; a hydraulic oil control valve unit provided between the swing motor and the swing valve and configured to control the flow of the hydraulic oil according to a pressure of the hydraulic oil at opposite ends; a first accumulator configured to store the hydraulic oil having passed through the hydraulic oil control valve unit when the swing motor is decelerated; a regeneration control valve provided between the hydraulic oil control valve unit and the first accumulator; a first pressure detection member provided between the swing motor and the swing valve and configured to detect a pressure of the hydraulic oil flowing into the swing motor; a second pressure detection member configured to detect a pressure discharged from the swing motor; and a controller configured to control the hydraulic oil control valve unit and the regeneration control valve by determining acceleration, deceleration or deceleration reverse lever of the swing motor according to a signal of the operation unit and a difference between the pressure detected by the first pressure detection member and the second pressure detection member, wherein the controller is configured to determine that the swing motor is in an acceleration state, in case where the rotation direction of the swing motor is selected to a first direction by the signal of the operation unit, if the pressure detected by the first pressure detection member is higher than the pressure detected by the second pressure detection member, to determine that the swing motor is in an deceleration state, in case where the rotation direction of the swing motor is selected to the first direction by the signal of the operation unit, if the pressure detected by the second pressure detecting member is higher than the pressure detected by the first pressure detecting member, and to determine that the swing motor is in deceleration reverse lever state, in case where the rotation direction of the swing motor is the first direction but the current rotation direction of the swing motor is selected to the opposite direction to the first direction by the signal of the operation unit, if the pressure detected by the second pressure detection member is higher than the pressure detected by the first pressure detection member.