A wireless communication apparatus (1 1) that carries out direct communication with other wireless communication apparatuses (1 2,..., 1 N) that are communication partners, comprising: a control unit that finds a factor that indicates wireless communication congestion that is an index indicating the amount of communication resulting from said other wireless communication apparatuses (1 2,..., 1 N) on wireless channels that carry out communication; a congestion control unit that determines a transmission power set value that is the value of transmission power of its own wireless communication apparatus (1 1) based on said factor that indicates wireless communication congestion and based on the values of transmission power for each of said other wireless communication apparatuses (1 2,..., 1 N); and a wireless unit that transmits to said other wireless communication apparatuses (1 2,..., 1 N) wireless signals that contain as information the transmission power set value at a transmission power that accords with said transmission power set value that was determined in said congestion control unit; wherein said congestion control unit is adapted to: set said transmission power set value to a plurality of levels that are set in advance; judge whether the transmission power of the wireless communication apparatuses (1 2,..., 1 N) is at the same level as or at a lower level than that of its own wireless communication apparatus (1 1) based on said transmission power set values that are received from said other wireless communication apparatuses (1 2,..., 1 N); compare said factor that indicates wireless communication congestion with a first threshold value that is set in advance; and lower said transmission power set value by one level when, from among a plurality of said other wireless communication apparatuses (1 2,..., 1 N), the transmission power of a proportion that has been set in advance of other wireless communication apparatuses (1 2,..., 1 N) is at the same level as or at a lower level than that of its own wireless communication apparatus (1 1) and when said factor that indicates wireless communication congestion exceeds said first threshold value. a control unit that finds a factor that indicates wireless communication congestion that is an index indicating the amount of communication resulting from said other wireless communication apparatuses (1 2,..., 1 N) on wireless channels that carry out communication; a congestion control unit that determines a transmission power set value that is the value of transmission power of its own wireless communication apparatus (1 1) based on said factor that indicates wireless communication congestion and based on the values of transmission power for each of said other wireless communication apparatuses (1 2,..., 1 N); and a wireless unit that transmits to said other wireless communication apparatuses (1 2,..., 1 N) wireless signals that contain as information the transmission power set value at a transmission power that accords with said transmission power set value that was determined in said congestion control unit; wherein said congestion control unit is adapted to: set said transmission power set value to a plurality of levels that are set in advance; judge whether the transmission power of the wireless communication apparatuses (1 2,..., 1 N) is at the same level as or at a lower level than that of its own wireless communication apparatus (1 1) based on said transmission power set values that are received from said other wireless communication apparatuses (1 2,..., 1 N); compare said factor that indicates wireless communication congestion with a first threshold value that is set in advance; and lower said transmission power set value by one level when, from among a plurality of said other wireless communication apparatuses (1 2,..., 1 N), the transmission power of a proportion that has been set in advance of other wireless communication apparatuses (1 2,..., 1 N) is at the same level as or at a lower level than that of its own wireless communication apparatus (1 1) and when said factor that indicates wireless communication congestion exceeds said first threshold value. set said transmission power set value to a plurality of levels that are set in advance; judge whether the transmission power of the wireless communication apparatuses (1 2,..., 1 N) is at the same level as or at a lower level than that of its own wireless communication apparatus (1 1) based on said transmission power set values that are received from said other wireless communication apparatuses (1 2,..., 1 N); compare said factor that indicates wireless communication congestion with a first threshold value that is set in advance; and lower said transmission power set value by one level when, from among a plurality of said other wireless communication apparatuses (1 2,..., 1 N), the transmission power of a proportion that has been set in advance of other wireless communication apparatuses (1 2,..., 1 N) is at the same level as or at a lower level than that of its own wireless communication apparatus (1 1) and when said factor that indicates wireless communication congestion exceeds said first threshold value.