To provide an environmental sensor with reduced power consumption.A semiconductor device includes a first sensor, a second sensor, a control circuit, a transmission amplifier, a modulation circuit, a memory device, an analog-to-digital converter circuit, and an antenna. The memory device and the analog-to-digital converter circuit each include a transistor in which an oxide semiconductor is formed in a channel region. The second sensor is an optical sensor, and has a function of transmitting a trigger signal to the control circuit when receiving laser light. The control circuit has a function of transmitting a control signal to the first sensor, the transmission amplifier, the modulation circuit, the memory device, and the analog-to-digital converter circuit when receiving the trigger signal. The first sensor is a sensor that senses a physical or chemical quantity, and the measured data is subjected to digital conversion by the analog-to-digital converter circuit and stored in the memory device. In addition, the data is transmitted as an electromagnetic wave signal from the antenna through the modulation circuit and the transmission amplifier.