An acoustic-propagation-time measuring apparatus includes an acoustic transmitting
and receiving section having an acoustic element capable of transmitting and receiving
acoustic waves, an A/D converter which converts an echo signal reflected from a
target object to be measured into a digital signal, an inverse-analysis section
that converts the digital echo signal into an impulse signal through inverse analysis
where the digital echo signal is multiplied by an inverse matrix, a calculating
section that measures an acoustic propagation time and a time difference based
on the digital echo signal converted to the impulse signal, and a display section
which displays the acoustic propagation time and time difference calculated by
the calculating section.