A problem is to provide a liquid crystal compound satisfying at least one physical property such as high stability to heat and light, high clearing point, low minimum temperature of liquid crystal phase, small viscosity, suitable optical anisotropy, large dielectric anisotropy, suitable elastic constant and excellent compatibility with other liquid crystal compounds, a liquid crystal composition containing the compound, and a liquid crystal display device including the composition.The compound is represented by formula (1). In formula (1), for example, R1 is alkenyl; ring A1 and ring A2 are 1,4-cyclohexylene or 1,4-phenylene; Z1, Z2, Z3 are a single bond or —COO—; X1 is hydrogen or fluorine; L1, L2, L3 and L4 are hydrogen or fluorine; and a and b are each independently 0 or 1, a sum of a and b is 1, and when a is 1, at least one of ring A1 and ring A2 is 1,4-cyclohexylene.