In non-inductive current drive steady state operation of tokamak reactor, it is desirable that the Q_cd value determined by the plasma current balance is the same as the Q value determined by the plasma energy balance [Progress in the ITER Physics Basis, Nucl. Fusion 47, S285 (2007)]. The more quantitative scaling laws of Q and Q_cd are derived from the scaling laws of electron density, beta ratio, energy confinement time and current drive efficiency. The reduced scaling laws of Q and Q_cd are examined by comparison with the data of the standard scenario of inductive operation and the reference scenario of non-inductive operation of ITER. Sensitivities of Q and Q_cd on the plasma parameters are studied and requirement is examined to satisfy Q_cd ≈ Q.