Spin-orbit torque (SOT) is a spin torque based on spin-orbit coupling in a nonmagnet/ferromagnet heterostructure. In this structure, transverse spin current that is generated by an in-plane charge current and exerts torque on the adjacent ferromagnetic layer. This is intensively investigated because it can be used to switch the ferromagnet effectively in various spintronic devices. Here, we discuss various experimental methods to evaluate the SOT in nonmagnet/ferromagnet bilayer structures.