A transmission management system, comprising: a receiver (51; 209) configured to receive a communication start request, in order to start communication between a first transmission terminal and a second transmission terminal; a reservation obtainer (61; 201) configured to obtain first reservation identification information for identifying communication reserved for the first transmission terminal, and second reservation identification information for identifying communication reserved for the second transmission terminal, respectively, using reservation information regarding communication reserved for at least the first transmission terminal and the second transmission terminal; and a reservation determiner (62; 201) configured to accept the communication start request or to reject the communication start request, with which the system is configured to operate characterized as follows: a) said reservation determiner (62; 201) being configured so that the communication start request is accepted when the first reservation identification information matches the second reservation identification information and the communication start request is rejected when the first reservation identification information does not match the second reservation identification information, b) wherein the receiver (51; 209) is configured to receive the communication start request from the first transmission terminal; c) wherein the receiver (51; 209) being configured to receive the communication start request which is including first terminal identification information of the first transmission terminal and second terminal identification information of the second transmission terminal, d) wherein the reservation obtainer (61; 201) being configured to identify said first reservation identification information in association with the first terminal identification information and said second reservation identification information is identified in association with the second terminal identification information. a receiver (51; 209) configured to receive a communication start request, in order to start communication between a first transmission terminal and a second transmission terminal; a reservation obtainer (61; 201) configured to obtain first reservation identification information for identifying communication reserved for the first transmission terminal, and second reservation identification information for identifying communication reserved for the second transmission terminal, respectively, using reservation information regarding communication reserved for at least the first transmission terminal and the second transmission terminal; and a reservation determiner (62; 201) configured to accept the communication start request or to reject the communication start request, with which the system is configured to operate characterized as follows: a) said reservation determiner (62; 201) being configured so that the communication start request is accepted when the first reservation identification information matches the second reservation identification information and the communication start request is rejected when the first reservation identification information does not match the second reservation identification information, b) wherein the receiver (51; 209) is configured to receive the communication start request from the first transmission terminal; c) wherein the receiver (51; 209) being configured to receive the communication start request which is including first terminal identification information of the first transmission terminal and second terminal identification information of the second transmission terminal, d) wherein the reservation obtainer (61; 201) being configured to identify said first reservation identification information in association with the first terminal identification information and said second reservation identification information is identified in association with the second terminal identification information. a) said reservation determiner (62; 201) being configured so that the communication start request is accepted when the first reservation identification information matches the second reservation identification information and the communication start request is rejected when the first reservation identification information does not match the second reservation identification information, b) wherein the receiver (51; 209) is configured to receive the communication start request from the first transmission terminal; c) wherein the receiver (51; 209) being configured to receive the communication start request which is including first terminal identification information of the first transmission terminal and second terminal identification information of the second transmission terminal, d) wherein the reservation obtainer (61; 201) being configured to identify said first reservation identification information in association with the first terminal identification information and said second reservation identification information is identified in association with the second terminal identification information.