A transmission control method includes: generating a write request for writing, to a blockchain, a transaction corresponding to a deal to be recorded in the blockchain; acquiring, from a node that performs a process for writing the transaction to the blockchain, load information that indicates an amount of load pertaining to the process to be performed by the node to write the transaction to the blockchain; and transmitting the write request to the node when a period during which the amount of the load indicated by the load information is less than a threshold reaches a specified time.