A current sensor includes an element that is in a high-resistance state when an absolute value of a current flowing between a first terminal and a second terminal is within a first range, and changes to a low-resistance state in which a resistance value is lower than that in the high-resistance state when the absolute value of the current exceeds the first range, and a circuit that supplies a current to be measured to the element, and senses a value of the current to be measured based on at least one of voltages of the first terminal and the second terminal.