An asynchronous bridge includes a transmission unit and a receiving unit. The transmission unit receives a write valid signal and input data from a master circuit, outputs write addresses increment under control of the write valid signal, sequentially stores the input data in memory cells, as directed by write addresses, and then sequentially outputs the stored input data, as directed by read addresses. The receiving unit receives a read ready signal from a slave circuit, determines whether memory cells are valid, based on the write addresses and the read addresses, and then outputs a read valid signal and the input data, based on the determination.