Hydraulic system for working machine and control method of the hydraulic system

A hydraulic system for a working machine, comprising:

• a boom cylinder to move a boom upward and downward;
• a working tool cylinder to move a working tool attached to the boom;
• a boom control valve to control the boom cylinder;
• a working tool control valve to control the working tool cylinder;
• a horizontal control valve including a switching valve having:
• an activating position to allow a horizontalizing operation of the working tool;
• and
• a stopping position to stop the horizontalizing operation;
• and
• a controller device having:
• a first information obtaining portion to obtain permission and non-permission to the horizontalizing operation by the horizontal control valve;
• a second information obtaining portion to obtain at least either one of upward operation of the boom and upward movement of the boom;
• and
• a horizontal controller to set the switching valve from the activating position to the stopping position when the first information obtaining portion obtains the non-permission and the second information obtaining portion obtains either one of the upward operation of the boom and the upward movement of the boom, wherein
• the horizontal controller holds the switching valve at the activating position when the first information obtaining portion has obtained the non-permission and the second information obtaining portion has not obtained at least either one of the upward operation of the boom and the upward movement of the boom.