Ultrasonic inspection of joined portions of packaging containers

An ultrasonic inspection device for inspecting a packaging container having a joined portion including overlapping and joined edges of the packaging container, comprising:

• a transmitter configured to irradiate ultrasonic waves;
• and
• a plurality of receivers, each of the plurality of receivers having a reception surface configured to receive ultrasonic waves that have transmitted through the joined portion,
• wherein the transmitter comprises:
• a transmission main body that irradiates the ultrasonic waves;
• and
• a mirror configured to reflect first ultrasonic waves irradiated from the transmission main body,
• wherein the transmission main body comprises an irradiation surface that irradiates the ultrasonic waves, the irradiation surface comprising an inner region that irradiates the first ultrasonic waves and a peripheral region disposed outside the inner region and that irradiates second ultrasonic waves, and
• wherein the mirror is arranged such that:
• the mirror reflects the first ultrasonic waves irradiated from the inner region of the irradiation surface without reflecting the second ultrasonic waves irradiated from the peripheral region of the irradiation surface, and
• the first ultrasonic waves irradiated from the inner region of the irradiation surface and reflected by the mirror travel to at least a base end portion of the joined portion.