On 15 April 2023, a man threw a cylindrical explosive at Kishida shortly before he was due to make a campaign speech in Wakayama.

The device exploded after a short delay during which Kishida was evacuated from the scene unharmed. Ryuji Kimura, a 24-year-old man from Hyogo Prefecture, was arrested at the scene, with cameras showing him holding what appeared to be a second cylindrical object as he was tackled to the ground. The incident took place as Kishida was talking with a candidate of the ruling Liberal Democratic Party just before his scheduled speech. Kishida immediately left by car after the incident and continued with his stump speech elsewhere in the city. He stated at an event later in the day that "elections are a bedrock of democracy," adding that it was extremely unforgiveable that such violence took place.