In this study, the pressure-induced phase transition of the 3d transition metal titanium (Ti) has been investigated at pressures up to 290GPa at room temperature using an x-ray diffraction technique with a micro-beam. From the analysis of powder x-ray diffraction patterns, the high-pressure delta phase (orthorhombic, Cmcm) was found to transform to the beta phase (body-centered cubic: bcc, Im3m) at 243GPa. Although the volume reduction at this phase transition was less than 1%, the coexistence of the delta phase suggests that the transition is of the first order. The isothermal bulk modulus at zero pressure, B-0, and the pressure derivative of B-0, B-0 ', were estimated to be 125(2)GPa and 3.46(6)GPa, respectively, by least squares fitting to the Vinet equation of state based on the P-V data of the delta and beta phases. This transition to the bcc phase verified predictions from theoretical studies and demonstrated the systematics of the pressure-induced structural phase transition in transition metals.