Seebeck and Nernst coefficients were numerically calculated by solving the Boltzmann equation with relaxation time approximation for bismuth under a magnetic field as functions of the products of cyclotron frequency (ω c) and relaxation time (τ 0), taking into consideration the scattering process of carriers as a function of energy. The relationship between ω c τ 0 and magnitude of the magnetic field was derived from the definition of mobility, and each coefficient was estimated as a function of the magnetic field. The magneto-Seebeck coefficient was estimated by the addition of the Seebeck coefficient to the Nernst coefficient, and the contribution of thermoelectric effect in the presence of the magnetic field was dominant, being derived from the Seebeck effect. The magnetic field and temperature dependences of the magneto-Seebeck coefficient were evaluated by the use of a two-carrier model and mobility of single-crystal bismuth. The results show that the magneto-Seebeck coefficient can be improved by a factor of 1.3 to 1.4 in the presence of a magnetic field to control the scattering process of the carriers.