This on-vehicle communication device includes: a storage unit configured to store correspondence information indicating a correspondence relationship between an address and a port number; and a communication unit configured to perform, by using the correspondence information, filtering of a packet having been received. A target port number which is a port number of a target instrument is registered in advance in the correspondence information. In the filtering, the communication unit selectively allows a packet that includes the target port number, to pass. The communication unit performs an address registration process of acquiring an address from the packet that includes the target port number and registering, into the correspondence information, the acquired address in association with the target port number. In the filtering after the address registration process, the communication unit selectively allows a packet that includes the target port number and the corresponding address, to pass.