A side impact load transmitting structure includes: a vehicular seat disposed in a cabin; a tunnel portion that is disposed such that it protrudes upward into the cabin and extends in a front-rear direction of a vehicle body; a load transmitting member including a load receiving portion that is disposed at the underside of the vehicular seat and receives a side impact load acting on a vehicle body side portion at the time of a side impact collision, with the load transmitting member being configured to transmit the side impact load received by the load receiving portion to the tunnel portion; and a downward movement suppressing member that suppresses the downward movement of the load transmitting member resulting from a downward load component of the side impact load.