An onboard communication apparatus that is installed in a vehicle and that is configured to perform communication with a roadside communication apparatus that provides channel use information and performs communication with other onboard communication apparatuses that are installed in other vehicles, the channel use information including at least information that indicate a plurality of channels having different frequencies, said onboard communication apparatus comprising: a first communication unit that is configured to communicate by way of a channel whose frequency band is fixed; a second communication unit that is configured to communicate by way of a channel that differs from the channel used in said first communication unit; a determination unit that is configured to determine whether or not communication with said roadside communication apparatus is direct communication that is not relayed by another onboard communication apparatus; an application unit that is configured to designate one channel from among the plurality of channels that are included in the channel use information; and a channel setting unit that is configured to switch the channel of said second communication unit to a designated channel that is designated by said application unit, wherein, when direct communication with said roadside communication apparatus is not possible, said second communication unit communicates with said roadside communication apparatus by way of another onboard communication apparatus that is communicating with said roadside communication apparatus, and wherein said application unit uses the designated channel to transmit a path verification message to said roadside communication apparatus when receiving the channel use information through said second communication unit, and causes said channel setting unit to perform a channel switching operation to the designated channel when receiving, from said roadside communication apparatus, a path verification response message that is a response to the path verification message. a first communication unit that is configured to communicate by way of a channel whose frequency band is fixed; a second communication unit that is configured to communicate by way of a channel that differs from the channel used in said first communication unit; a determination unit that is configured to determine whether or not communication with said roadside communication apparatus is direct communication that is not relayed by another onboard communication apparatus; an application unit that is configured to designate one channel from among the plurality of channels that are included in the channel use information; and a channel setting unit that is configured to switch the channel of said second communication unit to a designated channel that is designated by said application unit, wherein, when direct communication with said roadside communication apparatus is not possible, said second communication unit communicates with said roadside communication apparatus by way of another onboard communication apparatus that is communicating with said roadside communication apparatus, and wherein said application unit uses the designated channel to transmit a path verification message to said roadside communication apparatus when receiving the channel use information through said second communication unit, and causes said channel setting unit to perform a channel switching operation to the designated channel when receiving, from said roadside communication apparatus, a path verification response message that is a response to the path verification message.