A liquid crystal composition having at least one or a suitable balance regarding at least two of characteristic such as high maximum temperature of a nematic phase, low minimum temperature thereof, small viscosity, suitable optical anisotropy, large dielectric anisotropy, large specific resistance, high stability to ultraviolet-light or heat, or large elastic constant; an AM-device having short response time, a large voltage holding ratio, low threshold voltage, a large contrast ratio, a negatively large DC brightness relaxation time constant and long-service-life. The liquid crystal composition contains a compound contributing to high stability to heat or ultraviolet-light as an additive component and a specific compound having positively large dielectric anisotropy, and a liquid crystal display device includes the composition. The composition may contain a specific compound having high maximum temperature or small viscosity as a second component or a specific compound having negative dielectric anisotropy as a third component.