It is a US propaganda leaflet that is encouraging the Japanese people to not fall for the propaganda and lies spread by the Japanese military/government/press.
For example, the lines coming out of the radio microphone are examples of headlines or news items that were spread by the Japanese media, and the dates they were published or announced, but were later proven to be false. For example
"Our army has destroyed the American navy's main forces" (Jan 20th, 1943)
"The US and European powers naval forces have been eliminated, and the Pacific Ocean is under Japan's control" (September 28th, 1942)
etc...
Basically, it's asking the Japanese people to think for themselves, and to not trust a government that lies so blatantly to its people.