Out of Japan's 220,000 police officers, only 500 are professional investigators. This comparison alone shows the difficulty of passing such an exam.,If you have a high school diploma, your salary would be around 190,000 yen. For a junior college (similar to a vocational school), it's 200,000 yen. A university degree (bachelor's or above) would earn you 230,000 yen per month. The average salary for regular employees is 198,000 yen per month.,And according to the type of police work, there are also a variety of allowances that can be received, such as patrol allowances for patrol officers and traffic management allowances for traffic police.。