Provided is a data replication method capable of reducing the number of communication times when a processing result of an active system is replicated to a standby system. The data replication method, in which a first computer receives a first message containing a first processing request, and a plurality of second computers replicates the first message, includes the steps of: sending, by a third computer, the first message to the first computer and the second computers; sending, by each of the second computers, a message receive notification of the first message to the first computer; sending, by the first computer, after reception of the message receive notification from the second computers, the message receive notification of the first message to the third computer; and sending, by the first computer, a notification indicating that the first processing request becomes executable by the first computer to the second computers.