A hydraulic excavator comprising: a main body (1, 2) including an upper swing structure and a lower track structure; a boom pivotably coupled to the main body (1, 2); an arm pivotably coupled to a distal end portion of the boom; a bucket pivotably coupled to a distal end portion of the arm; a first hydraulic pump; a second hydraulic pump; a boom cylinder or a bucket cylinder to which hydraulic fluid is supplied from the first hydraulic pump and the second hydraulic pump to drive the boom or the bucket; an arm cylinder to which hydraulic fluid is supplied from the first hydraulic pump to drive the arm; a first operation device (25, 27) that issues an instruction on operation of the boom cylinder or the bucket cylinder; a second operation device that issues an instruction on operation of the arm cylinder; a first directional control valve (18, 22) that controls a direction and a flow rate of hydraulic fluid to be supplied from the first hydraulic pump to the boom cylinder or the bucket cylinder in response to an operation amount of the first operation device (25, 27); a second directional control valve that controls a direction and a flow rate of hydraulic fluid to be supplied from the first hydraulic pump to the arm cylinder in response to an operation amount of the second operation device; and a third directional control valve that controls a direction and a flow rate of hydraulic fluid to be supplied from the second hydraulic pump to the arm cylinder in response to an operation amount of the second operation device, wherein the first directional control valve (18, 22) and the second directional control valve being tandem connected to a center bypass line of the first hydraulic pump and being connected in parallel to a parallel line branched from the center bypass line, and the hydraulic excavator including a spool stroke limitation device (30, 100) that is configured to, in a case where the first operation device (25, 27) and the second operation device are operated simultaneously, limit a spool stroke amount of the second directional control valve in response to an operation amount of the first operation device (25, 27) in a state in which a spool stroke amount of the third directional control valve is controlled in response to an operation amount of the second operation device, characterized in that the hydraulic excavator includes a center bypass flow control valve that is arranged at a most downstream of the center bypass line and limits a flow rate of hydraulic fluid passing through the center bypass line in response to an operation amount of the second operation device in a case where the second operation device is operated. a main body (1, 2) including an upper swing structure and a lower track structure; a boom pivotably coupled to the main body (1, 2); an arm pivotably coupled to a distal end portion of the boom; a bucket pivotably coupled to a distal end portion of the arm; a first hydraulic pump; a second hydraulic pump; a boom cylinder or a bucket cylinder to which hydraulic fluid is supplied from the first hydraulic pump and the second hydraulic pump to drive the boom or the bucket; an arm cylinder to which hydraulic fluid is supplied from the first hydraulic pump to drive the arm; a first operation device (25, 27) that issues an instruction on operation of the boom cylinder or the bucket cylinder; a second operation device that issues an instruction on operation of the arm cylinder; a first directional control valve (18, 22) that controls a direction and a flow rate of hydraulic fluid to be supplied from the first hydraulic pump to the boom cylinder or the bucket cylinder in response to an operation amount of the first operation device (25, 27); a second directional control valve that controls a direction and a flow rate of hydraulic fluid to be supplied from the first hydraulic pump to the arm cylinder in response to an operation amount of the second operation device; and a third directional control valve that controls a direction and a flow rate of hydraulic fluid to be supplied from the second hydraulic pump to the arm cylinder in response to an operation amount of the second operation device, wherein the first directional control valve (18, 22) and the second directional control valve being tandem connected to a center bypass line of the first hydraulic pump and being connected in parallel to a parallel line branched from the center bypass line, and the hydraulic excavator including a spool stroke limitation device (30, 100) that is configured to, in a case where the first operation device (25, 27) and the second operation device are operated simultaneously, limit a spool stroke amount of the second directional control valve in response to an operation amount of the first operation device (25, 27) in a state in which a spool stroke amount of the third directional control valve is controlled in response to an operation amount of the second operation device, characterized in that the hydraulic excavator includes a center bypass flow control valve that is arranged at a most downstream of the center bypass line and limits a flow rate of hydraulic fluid passing through the center bypass line in response to an operation amount of the second operation device in a case where the second operation device is operated.