A transporter of an embodiment has a transporter, a detector, and a controller. The transporter holds a selected object from among a plurality of objects and transports the selected object in a first direction in a first state, and then configured to transport the selected object, while holding the selected object, in a second direction different from the first direction and not anti-parallel to the first direction, in a second state. The detector detects a change from the first state to the second state, wherein, in the second state, the transporter can transport the selected object in the second direction without disturbance by the presence of any other object than the selected object. The controller stops transporting the selected object in the first direction, in case that the detector detected the change from the first state to the second state.