A PLD in which a configuration memory is formed using a nonvolatile memory with a small number of transistors and in which the area of a region where the configuration memory is disposed is reduced is provided. Further, a PLD that is easily capable of dynamic reconfiguration and has a short startup time is provided. A programmable logic device including a memory element, a selector, and an output portion is provided. The memory element includes a transistor in which a channel is formed in an oxide semiconductor film, and a storage capacitor and an inverter which are connected to one of a source and a drain of the transistor. The inverter is connected to the selector. The selector is connected to the output portion.