A path selection apparatus in a sensor tree includes a node moving unit that selects a first node in the sensor tree, and moves a second node to under a third node in the sensor tree if the total number of packets transmitted and received in the sensor tree is reduced as a result of the second node being moved to under the third node, the first node having a child node under the first node, the second node being located under a subtree of which a vertex is the first node, the third node not belonging to the subtree. If nodes under the subtree of which the vertex is the first node do not include anode that reduces the total number of packets as a result of being moved, the node moving unit moves a node that is included in the nodes under the subtree and does not change the total number of packets, to under the third node.