  By using numerical simulation, we confirm that Takayasu--Sato--Takayasu (TST)
model which leads Pareto's law satisfies the detailed balance under Gibrat's
law. In the simulation, we take an exponential tent-shaped function as the
growth rate distribution. We also numerically confirm the reflection law
equivalent to the equation which gives the Pareto index $\mu$ in TST model.
Moreover, we extend the model modifying the stochastic coefficient under a
Non-Gibrat's law. In this model, the detailed balance is also numerically
observed. The resultant pdf is power-law in the large scale Gibrat's law
region, and is the log-normal distribution in the middle scale Non-Gibrat's
one. These are accurately confirmed in the numerical simulation.
