The metamagnetic behaviour, which corresponds to one of the characteristic properties in the heavy fermion compounds, was studied by measuring the electrical resistivity under pressure and magnetic field for a typical heavy fermion compound CeCu6 with orthorhombic structure. The transverse magnetoresistance at 100 mK indicated a peak structure at Hm = 20 kOe for the magnetic field H//c-axis under ambient pressure. Hm is found to increase linearly as a function of pressure and indicates Hm = 102 kOe at 1.75 GPa, for example. The quantum critical point is thus likely to exist at a slightly negative pressure value of ∼ 0.21 GPa from extrapolating Hm to zero. The ρ0 and A values in the electrical resistivity ρ = ρ0+AT2 decrease steeply in magnitude with increasing pressure and magnetic field, indicating that the heavy fermion state is destroyed by pressure and magnetic field. © 2011 The Physical Society of Japan.