A working machine (1, 100, 200, 300) comprising: a housing; a motor accommodated in the housing; an operating part (4, 104, 304, 206) which is a part of the housing, the operating part being movable between an on position and an off position, the motor being driven when the operating part is in the on position, and the motor being stopped when the operating part is in the off position; and an on-locking means (5, 105, 205, 305) capable of maintaining the motor in a driving state; wherein at least a portion of the on-locking means is not exposed prior to performing an operation to turn on the motor, and the portion of the on-locking means is exposed by performing the operation to turn on the motor such that the on-locking means becomes operable, characterised in that: the operating part (4, 104, 304, 206) has a shielding part (44, 45, 42); wherein the shielding part (44, 45, 42) is provided on an outer peripheral wall of the housing so as to form an internal space between the shielding part (44, 45, 42) and the housing; wherein an entire part of the on-locking means is positioned in the internal space when the operating part is in the off position, or wherein an amount that the on-locking means protrudes from the internal space when the operating part is in the on position is greater than an amount that the on-locking means protrudes from the internal space when the operating part is in the off position. a housing; a motor accommodated in the housing; an operating part (4, 104, 304, 206) which is a part of the housing, the operating part being movable between an on position and an off position, the motor being driven when the operating part is in the on position, and the motor being stopped when the operating part is in the off position; and an on-locking means (5, 105, 205, 305) capable of maintaining the motor in a driving state; wherein at least a portion of the on-locking means is not exposed prior to performing an operation to turn on the motor, and the portion of the on-locking means is exposed by performing the operation to turn on the motor such that the on-locking means becomes operable, characterised in that: the operating part (4, 104, 304, 206) has a shielding part (44, 45, 42); wherein the shielding part (44, 45, 42) is provided on an outer peripheral wall of the housing so as to form an internal space between the shielding part (44, 45, 42) and the housing; wherein an entire part of the on-locking means is positioned in the internal space when the operating part is in the off position, or wherein an amount that the on-locking means protrudes from the internal space when the operating part is in the on position is greater than an amount that the on-locking means protrudes from the internal space when the operating part is in the off position. the operating part (4, 104, 304, 206) has a shielding part (44, 45, 42); wherein the shielding part (44, 45, 42) is provided on an outer peripheral wall of the housing so as to form an internal space between the shielding part (44, 45, 42) and the housing; wherein an entire part of the on-locking means is positioned in the internal space when the operating part is in the off position, or wherein an amount that the on-locking means protrudes from the internal space when the operating part is in the on position is greater than an amount that the on-locking means protrudes from the internal space when the operating part is in the off position.