A node information detection apparatus identifies the type of an Operating System (OS) operating on a node that is connected via a network. A message transmission unit transmits a transmission message to be responded to through IPv6 protocol stack processing that is executed at a kernel level implemented in at least one or more types of OSs. A message reception unit receives a response message from the node that received the transmission message. An OS type identification unit identifies the type of OS operating on the node on the basis of the contents of the response message received from the node or on the basis of presence or absence of a response message from the node.