To provide a liquid crystal composition satisfying at least one characteristic such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large dielectric anisotropy, large specific resistance, high stability to ultraviolet light, high stability to heat and large elastic constant, or has a suitable balance between at least two of these characteristics. To provide an AM device having short response time, large voltage holding ratio, low threshold voltage, large contrast ratio, long service life and so forth. A liquid crystal composition that has a nematic phase and that comprises a compound having large dielectric anisotropy as a first component and a compound having small viscosity as a second component, and may comprise a compound having high maximum temperature or small viscosity as a third component and a compound having a large dielectric anisotropy as a fourth component, and a liquid crystal display device comprising this composition.