PROBLEM TO BE SOLVED: To provide a respiratory waveform drawing system capable of presenting a waveform indicating respiration of a subject almost in real time.SOLUTION: A respiratory waveform drawing system for drawing a respiratory waveform of a subject on the bed includes: a plurality of load detectors provided on the bed or at a leg lower part of the bed for detecting a load of the subject； a gravity position calculation part for obtaining a gravity position of the subject based on the load of the subject； a vibration coordinate setting part for obtaining a first extreme point which is a gravity position where a distance of the gravity position displaced from an initial origin becomes maximum, obtaining a second extreme point which is a gravity position where a distance from the initial origin appearing on the side opposite to the first extreme point of the initial origin, the initial origin being the gravity position at a certain time point, setting the direction connecting the first extreme point and the second extreme point as a temporary vibration axis, and setting a middle point of the first extreme point and the second extreme point as a temporary vibration origin； and a waveform drawing part for drawing the respiratory waveform by indicating the displacement from the temporary vibration origin of the gravity position projected on the temporary vibration axis with respect to a time.SELECTED DRAWING: Figure 10【課題】被験者の呼吸を示す波形を、ほぼリアルタイムで提示することのできる呼吸波形描画システムを提供する。【解決手段】 ベッド上の被験者の呼吸波形を描画する呼吸波形描画システムは、ベッド又はベッドの脚下に設けられ、被験者の荷重を検出する複数の荷重検出器と、前記被験者の荷重に基づいて被験者の重心位置を求める重心位置算出部と、ある時刻の重心位置を初期原点として、初期原点から変位する重心位置の距離が最大となる重心位置である第１極値点を求め、初期原点の第１極値点と反対側に現れる初期原点からの距離が最大になる重心位置である第２極値点を求め、第１極値点と第２極値点とを結ぶ方向を仮振動軸と設定し、第１極値点と第２極値点の中点を仮振動原点と設定する振動座標設定部と、前記仮振動軸上に投影した重心位置の前記仮振動原点からの変位を時間に対して表すことによって前記呼吸波形を描画する波形描画部とを備える。【選択図】図１０
