Flooding protocols are efficient for communications on in stable network such as inter-vehicle communications because there is no necessity of complex procedures to build routes for data forwarding. In this paper, we propose a multi-channel flooding protocol using multi-interface WLAN terminals for improving robustness of communications. In simulation test, we show that packet loss rate can be reduced with parallel-redundant packet transmission using multi-channel, and transmission delay can also be reduced compared to serial-redundant packet transmission using single-channel. In experimental test, we confirm that the multi-channel flooding is also effective in real environment.