Inspection device and inspection method

An inspection device, comprising:

• a transmitter configured to transmit a first ultrasonic wave, the first ultrasonic wave including a plurality of burst waves having a first period Tp;
• a receiver on which the first ultrasonic wave is incident, the receiver being configured to output a signal corresponding to the incident first ultrasonic wave;
• and
• a supporter provided between the transmitter and the receiver,
• the supporter being configured to support an inspection object,
• the first period Tp (s), a distance Dx (m), and a velocity vx (m/s) satisfying
• 2Dx/((n+1)·vx)<Tp<2Dx/(n·vx),
• n being 1 or 2,
• the distance Dx being a shorter distance of a first distance and a second distance,
• the first distance being a distance along a first direction between the transmitter and the supporter,
• the first direction being from the transmitter toward the receiver,
• the second distance being a distance along the first direction between the supporter and the receiver,
• the velocity vx being a propagation velocity of the first ultrasonic wave in space between the transmitter and the receiver.