A work machine comprising: a travel structure; a swing structure swingably attached onto the travel structure; a multijoint work implement that is attached to the swing structure and that includes a boom, an arm, and a bucket; an operation device (45, 46, 47) configured to output an action direction to each of the travel structure, the swing structure, the boom, the arm, and the bucket in response to an operator's operation; and a controller configured to execute region limiting control to forcibly raise the boom in such a manner that a position of a tip end of the work implement is kept on a target excavation surface and within a region above the target excavation surface when the operation device (45, 46) issues an action direction to the arm or the bucket, wherein the controller includes a target action determination section configured to determine which is selected, as a control mode over a raising speed of the boom at a time of executing the region limiting control, a first mode or a second mode specified by a raising speed lower than a raising speed of the first mode when the tip end of the work implement is located below the target excavation surface, and to control the raising speed of the boom during the region limiting control based on a result of determination by the target action determination section, characterized in that the target action determination section configured to make the determination based on a penetration amount of the tip end of the work implement into the target excavation surface, to select the second mode when the penetration amount is equal to or higher than a predetermined value, and to select the first mode when the penetration amount is lower than the predetermined value. a travel structure; a swing structure swingably attached onto the travel structure; a multijoint work implement that is attached to the swing structure and that includes a boom, an arm, and a bucket; an operation device (45, 46, 47) configured to output an action direction to each of the travel structure, the swing structure, the boom, the arm, and the bucket in response to an operator's operation; and a controller configured to execute region limiting control to forcibly raise the boom in such a manner that a position of a tip end of the work implement is kept on a target excavation surface and within a region above the target excavation surface when the operation device (45, 46) issues an action direction to the arm or the bucket, wherein the controller includes a target action determination section configured to determine which is selected, as a control mode over a raising speed of the boom at a time of executing the region limiting control, a first mode or a second mode specified by a raising speed lower than a raising speed of the first mode when the tip end of the work implement is located below the target excavation surface, and to control the raising speed of the boom during the region limiting control based on a result of determination by the target action determination section, includes a target action determination section configured to determine which is selected, as a control mode over a raising speed of the boom at a time of executing the region limiting control, a first mode or a second mode specified by a raising speed lower than a raising speed of the first mode when the tip end of the work implement is located below the target excavation surface, and to control the raising speed of the boom during the region limiting control based on a result of determination by the target action determination section, characterized in that the target action determination section configured to make the determination based on a penetration amount of the tip end of the work implement into the target excavation surface, to select the second mode when the penetration amount is equal to or higher than a predetermined value, and to select the first mode when the penetration amount is lower than the predetermined value.