A small-sized hydraulic excavator comprising: an automotive lower traveling structure; an upper revolving structure that is mounted on the lower traveling structure to be capable of revolving thereon; and a front device that is provided on a front side of the upper revolving structure to be capable of lifting and tilting thereto, the upper revolving structure including; a revolving frame on a front side of which a base end of the front device is mounted, a driver's seat for an operator to sit on, a floor plate that is provided on the revolving frame to be located on a front side of the driver's seat and forms a foothold for the operator who sits on the driver's seat, and a protection member that is provided on the front side of the upper revolving structure and is configured to protect the operator who sits on the driver's seat, characterized in that; the revolving frame is provided with a left front protruding part and a right front protruding part that are respectively disposed to be separated in a left-right direction on a front side of the bottom plate to interpose the front device therebetween and protrude forward, and the protection member includes; a left base support column that is formed of a rod-shaped body extending in an upper-lower direction and has a lower end mounted on the left front protruding part of the revolving frame, a right base support column that is formed of a rod-shaped body extending in the upper-lower direction and has a lower end mounted on the right front protruding part of the revolving frame, a left intermediate support column that is mounted to an upper end of the left base support column via a left height adjustment mechanism to be capable of performing height adjustment in the upper-lower direction, a right intermediate support column that is mounted to an upper end of the right base support column via a right height adjustment mechanism to be capable of performing height adjustment in the upper-lower direction, and a canopy member that is mounted to an upper end of the left intermediate support column and an upper end of the right intermediate support column respectively via an angle adjustment mechanism and projects above the driver's seat in a state where adjustment of mounting angles to the left intermediate support column and the right intermediate support column is possible. an automotive lower traveling structure; an upper revolving structure that is mounted on the lower traveling structure to be capable of revolving thereon; and a front device that is provided on a front side of the upper revolving structure to be capable of lifting and tilting thereto, the upper revolving structure including; a revolving frame on a front side of which a base end of the front device is mounted, a driver's seat for an operator to sit on, a floor plate that is provided on the revolving frame to be located on a front side of the driver's seat and forms a foothold for the operator who sits on the driver's seat, and a protection member that is provided on the front side of the upper revolving structure and is configured to protect the operator who sits on the driver's seat, characterized in that; the revolving frame is provided with a left front protruding part and a right front protruding part that are respectively disposed to be separated in a left-right direction on a front side of the bottom plate to interpose the front device therebetween and protrude forward, and the protection member includes; a left base support column that is formed of a rod-shaped body extending in an upper-lower direction and has a lower end mounted on the left front protruding part of the revolving frame, a right base support column that is formed of a rod-shaped body extending in the upper-lower direction and has a lower end mounted on the right front protruding part of the revolving frame, a left intermediate support column that is mounted to an upper end of the left base support column via a left height adjustment mechanism to be capable of performing height adjustment in the upper-lower direction, a right intermediate support column that is mounted to an upper end of the right base support column via a right height adjustment mechanism to be capable of performing height adjustment in the upper-lower direction, and a canopy member that is mounted to an upper end of the left intermediate support column and an upper end of the right intermediate support column respectively via an angle adjustment mechanism and projects above the driver's seat in a state where adjustment of mounting angles to the left intermediate support column and the right intermediate support column is possible.