A working machine including: a machine body ; a boom pivotally having a base end portion pivotally supported by the machine body to turn about a first turn shaft ; a boom cylinder to turn the boom around the first turn shaft, the boom cylinder being arranged on one surface side of the boom; an arm having a base end portion pivotally supported by a tip end portion of the boom to turn about a second turn shaft parallel to the first turn shaft; an arm cylinder to turn the arm about the second turn shaft, the arm cylinder being arranged on another surface side of the boom; and a working tool pivotally supported by a tip end portion of the arm to turn about a third turn shaft parallel to the first turn shaft, the working machine comprising a controller device to set an allowable-stroke range of the arm cylinder moving the arm toward the boom depending on a turn position of the boom such that a shortest trajectory distance that is a shortest distance between the boom cylinder and a turn trajectory (M3) of the tip end portion of the working tool about the third turn shaft is kept at a predetermined value (L1) even when the turn position of the boom changes, in a case where the boom is turned in a direction deviating from a boom reference position (S1), the boom reference position being the turn position of the boom where a first straight line connecting the first turn shaft and a fourth turn shaft is perpendicular to a second straight line parallel to a longitudinal axis of the boom cylinder, the fourth turn shaft being provided on the base end portion side of the boom and rotatably supporting the boom cylinder, characterized in that the controller device sets the allowable-stroke range of the arm cylinder to be longer as the boom is turned in the direction deviating from the boom reference position. a machine body ; a boom pivotally having a base end portion pivotally supported by the machine body to turn about a first turn shaft ; a boom cylinder to turn the boom around the first turn shaft, the boom cylinder being arranged on one surface side of the boom; an arm having a base end portion pivotally supported by a tip end portion of the boom to turn about a second turn shaft parallel to the first turn shaft; an arm cylinder to turn the arm about the second turn shaft, the arm cylinder being arranged on another surface side of the boom; and a working tool pivotally supported by a tip end portion of the arm to turn about a third turn shaft parallel to the first turn shaft, the working machine comprising a controller device to set an allowable-stroke range of the arm cylinder moving the arm toward the boom depending on a turn position of the boom such that a shortest trajectory distance that is a shortest distance between the boom cylinder and a turn trajectory (M3) of the tip end portion of the working tool about the third turn shaft is kept at a predetermined value (L1) even when the turn position of the boom changes, in a case where the boom is turned in a direction deviating from a boom reference position (S1), the boom reference position being the turn position of the boom where a first straight line connecting the first turn shaft and a fourth turn shaft is perpendicular to a second straight line parallel to a longitudinal axis of the boom cylinder, the fourth turn shaft being provided on the base end portion side of the boom and rotatably supporting the boom cylinder, characterized in that the controller device sets the allowable-stroke range of the arm cylinder to be longer as the boom is turned in the direction deviating from the boom reference position. <EOS>