A minute current measurement method is provided. In the current measurement method, a first potential is applied to a first terminal of a transistor under test, a second potential is applied to a first terminal of a first transistor, the first transistor is turned on to accumulate a predetermined charge in a node electrically connecting a second terminal of the transistor under test with a second terminal of the first transistor, a third potential of an output terminal of a read circuit electrically connected to the node is measured, the first transistor is turned off, a fourth potential of the output terminal of the read circuit electrically connected to the node is measured, the amount of the charge held by the node is estimated from the amount of change in the potential of the output terminal of the read circuit (e.g., a difference between the third potential and the fourth potential), and a value of current flowing between the first terminal of the transistor under test and the second terminal of the first transistor is calculated from the amount of the charge held by the node.