A communication apparatus comprising: a generator configured to generate a message to be transmitted; wherein the message has a message type wherein the message type is at least one of a Cooperative Awareness Message, CAM, type of message and a Decentralized Environmental Notification Message, DENM, type of message; wherein a DENM message type has transmission conditions and a CAM message type has no transmission conditions; wherein the transmission conditions include a transmission distance and/or transmission delay time; wherein the transmission conditions are pre-stored; and wherein the DENM message type corresponds to particular events, the particular events being associated with the transmission conditions; a controller configured to perform a congestion control operation in which transmission of the message to be transmitted is controlled to control a congestion and wherein the controller is configured to control the congestion control operation in accordance with the type of the message to be transmitted, wherein: the controller is configured to change a method for transmitting the message in the congestion control operation in accordance with the type of message to be transmitted by changing at least one of a transmission interval, a transmission power and a transmission rate; when the message to be transmitted is a DENM type message, the controller is configured to perform the congestion control operation based on a degree of congestion of a radio channel that is used for message communication and the transmission conditions, and when the message to be transmitted is a CAM type message, the controller is configured to perform the congestion control operation based on the degree of congestion. a generator configured to generate a message to be transmitted; wherein the message has a message type wherein the message type is at least one of a Cooperative Awareness Message, CAM, type of message and a Decentralized Environmental Notification Message, DENM, type of message; wherein a DENM message type has transmission conditions and a CAM message type has no transmission conditions; wherein the transmission conditions include a transmission distance and/or transmission delay time; wherein the transmission conditions are pre-stored; and wherein the DENM message type corresponds to particular events, the particular events being associated with the transmission conditions; a controller configured to perform a congestion control operation in which transmission of the message to be transmitted is controlled to control a congestion and wherein the controller is configured to control the congestion control operation in accordance with the type of the message to be transmitted, wherein: the controller is configured to change a method for transmitting the message in the congestion control operation in accordance with the type of message to be transmitted by changing at least one of a transmission interval, a transmission power and a transmission rate; when the message to be transmitted is a DENM type message, the controller is configured to perform the congestion control operation based on a degree of congestion of a radio channel that is used for message communication and the transmission conditions, and when the message to be transmitted is a CAM type message, the controller is configured to perform the congestion control operation based on the degree of congestion. the controller is configured to change a method for transmitting the message in the congestion control operation in accordance with the type of message to be transmitted by changing at least one of a transmission interval, a transmission power and a transmission rate; when the message to be transmitted is a DENM type message, the controller is configured to perform the congestion control operation based on a degree of congestion of a radio channel that is used for message communication and the transmission conditions, and when the message to be transmitted is a CAM type message, the controller is configured to perform the congestion control operation based on the degree of congestion.