A child protector mechanism, comprising: a base member adapted to be assembled to a door of a vehicle; a first lever rotatably assembled to the base member and adapted to be linked with a latch mechanism; a second lever rotatably assembled to the base member and adapted to interlock with an inside door handle; a bush assembled so as to be movable with respect to the first lever and arranged between the first lever and the second lever, the bush being retainable at an unset position or a set position; a child protector lever that is assembled to the base member and is capable of moving the bush to the unset position or the set position; and wherein, under a state in which the bush is retained at the unset position, movement of the second lever is transmittable to the first lever through intermediation of the bush, and wherein, under a state in which the bush is retained at the set position, the second lever is idly swung with respect to the bush so that the movement of the second lever is untransmittable to the first lever, characterized by a position retaining means that is provided between the first lever and the bush and is capable of retaining the bush at each of the unset position and the set position with respect to the first lever, wherein the bush is sub-assembled to the first lever through intermediation of the position retaining means, and an assembly position of the first lever with respect to the base member is defined by: a support pin portion (11a1) that is provided on the base member and rotatably supports the first lever; an engagement wall (11a4) that is provided on the base member and engages with the first lever to define an initial position of the first lever; and an open lever that is rotatably assembled to the base member at a position between the latch mechanism and the first lever and engages with the first lever. a base member adapted to be assembled to a door of a vehicle; a first lever rotatably assembled to the base member and adapted to be linked with a latch mechanism; a second lever rotatably assembled to the base member and adapted to interlock with an inside door handle; a bush assembled so as to be movable with respect to the first lever and arranged between the first lever and the second lever, the bush being retainable at an unset position or a set position; a child protector lever that is assembled to the base member and is capable of moving the bush to the unset position or the set position; and wherein, under a state in which the bush is retained at the unset position, movement of the second lever is transmittable to the first lever through intermediation of the bush, and wherein, under a state in which the bush is retained at the set position, the second lever is idly swung with respect to the bush so that the movement of the second lever is untransmittable to the first lever, characterized by a position retaining means that is provided between the first lever and the bush and is capable of retaining the bush at each of the unset position and the set position with respect to the first lever, wherein the bush is sub-assembled to the first lever through intermediation of the position retaining means, and an assembly position of the first lever with respect to the base member is defined by: a support pin portion (11a1) that is provided on the base member and rotatably supports the first lever; an engagement wall (11a4) that is provided on the base member and engages with the first lever to define an initial position of the first lever; and an open lever that is rotatably assembled to the base member at a position between the latch mechanism and the first lever and engages with the first lever. a support pin portion (11a1) that is provided on the base member and rotatably supports the first lever; an engagement wall (11a4) that is provided on the base member and engages with the first lever to define an initial position of the first lever; and an open lever that is rotatably assembled to the base member at a position between the latch mechanism and the first lever and engages with the first lever.