From the expectation that quantum computers outperform their classical counterparts, huge efforts have been devoted to realizing them all over the world. However, their realization is hindered by several noises such as the fluctuation of frequency. Due to these noises, quantum computers may output incorrect computational results. Therefore, methods for verifying the correctness of outputs of quantum computers are highly desired to realize reliable quantum computers. In this talk, we first introduce a dilemma between quantum advantage and efficient verifiability. Then we give our verification method that resolves the dilemma for near-future quantum computers.