In case of diffusion combustion, a well-known “lifted flame” is formed. So far, we have focused on a combustion field in a triple-port burner. In the triple-port burner, since there are two boundaries of fuel and air, two flames are formed. Dependent on the flow condition, four flame configurations are observed, which are, (i) attached flames, (ii) inner lifted/outer attached flames, (iii) inner attached/outer lifted flames, (iv) twin lifted flames. Then, it is possible to study the interaction between two flames, which could give us useful information on turbulent flames. By changing flow conditions, we have investigated the transition between the attached flame and the lifted flame both by experimentally and numerically. In this study, by PIV/OH-PLIF simultaneous measurements, we examined the flow field and liftoff height of stationary and nonstationary flames. Results show that, as the liftoff height is larger, the minimum axial velocity around a base of the lifted flame increases. Also, the hysteresis characteristics of the inner and outer lifted flames are confirmed.