A memory system of an embodiment is connectable to a host and includes a nonvolatile memory and a memory controller. The memory controller includes: a signal line which transfers a signal sent from the host; a resistance element disposed between and electrically connected to the signal line and a wiring line given a reference potential of the memory system; a switching element connected serially to the resistance element and capable of switching a connection between the signal line and the wiring line; and a control circuit which controls the switching element to switch the connection between the signal line and the wiring line from a connected state to a disconnected state, when a change from a first potential to a second potential occurs on the signal line or when a change from the second potential to the first potential occurs on the signal line.