<p>A micro chemical system capable of controlling the flow of a specimen solution flowing in the flow passage of a microchip. In the micro chemical system (1), the T-shaped flow passage (4) comprising a main flow passage (2), an auxiliary flow passage (3), and a converging part (4) where the main flow passage (2) is converged with the auxiliary flow passage (3) is formed in the microchip (7). Panel heaters (8) and (9) are installed in the auxiliary flow passage (3) at positions where these heaters can heat the inside thereof. A hydrophobizing treatment is applied to the auxiliary flow passage (3) and the converging part (4), and water is supplied to the main flow passage (2) and air is supplied to the auxiliary flow passage (3).</p>
