Inspection device and inspection method

An inspection device, comprising:

• a transmitter configured to transmit a first ultrasonic wave;
• 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 receiving-side waveguide located between the receiver and an inspection position,
• the inspection position being between the transmitter and the receiver,
• the first ultrasonic wave passing through the receiving-side waveguide,
• an inspection object passing through the inspection position along a second direction crossing a first direction,
• the first direction being from the transmitter toward the receiver,
• the receiving-side waveguide including at least one of a first structure or a second structure,
• in the first structure:
• the receiving-side waveguide includes a tubular member and an inner member;
• the inner member is located inside the tubular member;
• and
• at least a portion of the inner member includes at least one of a mesh structure, a porous structure, or a surface unevenness structure,
• in the second structure:
• the receiving-side waveguide includes a tubular member;
• and
• at least a portion of the tubular member includes at least one of a mesh structure, a porous structure, or a surface unevenness structure.