The unidentified traffic sergeant, 40, stepped down from his position in the western megacity of Osaka on Dec 25, the mass-circulation newspaper Yomiuri Shimbun said.
He repeatedly ordered four younger officers to, in one sitting, stuff themselves with bulk meals such as 15 hamburgers, 15 doughnuts, four large-sized cups of instant fried noodles, or 3-4 litres of coffee-flavoured milk, the report said.
''After finding they were not working hard enough, I did it in order to toughen them up,'' the unnamed sergeant was quoted as telling investigators of the Osaka prefectural police headquarters.
The younger officers, in their 20s and 30s and assigned to two community police stations, were forced to binge on the meals when the sergeant visited them at work 10 times since early 2010, the report said.
He ordered the young policemen to buy the food and drink themselves out of their own pockets, and consume it inside their tiny ''koban (police box)'' stations as he watched.
A press officer at the prefectural police could not immediately confirm the report.