We define "BITAIKA" as a self posture adjustment system while sitting for correcting its posture. As a first step of developing BITAIKA system, we developed a system visually inducing a user to correct its posture. BITAIKA monitors one's posture to find a continuous bad posture using kinect and multiple piezoelectric sensors. When a bad posture continues, a window to assist for adjusting a posture pops up on PC monitor. We conducted the prototype experiment to evaluate the effectiveness of the system while PC work and confirmed that BITAIKA will effectively work as a posture adjustment system.