1. An image reconstruction method of transmitting and receiving signals to and from a measurement region and determining a quantity of a physical property of the measurement region through numerical calculation, the method characterized by comprising: a transmit-receive data acquisition step of transmitting and receiving signals to and from the measurement region; a physical property value calculation step of calculating a physical property value from an actual receive signal received from the measurement region; and a physical property value-display value conversion step of converting the physical property value into a display value, wherein the physical property value calculation step includes a step of calculating an estimate of a deviation quantity of an assumed physical property value, the estimate derived from the transmit-receive data acquired in the transmit-receive data, a distribution of the assumed physical property value, and an equation formed in consideration of and a wave propagation, and outputs a sum of the assumed physical property value and the deviation quantity as a calculated physical property value.