TOKYO, Japan (CNN) -- A 54-year-old Japanese father was arrested after he tried to help his son pass an exam by impersonating the young man and taking the test for him, police said Thursday.

The father, who was not named, put on glasses and straightened his hair to look more like the picture on his son's identity card, said Masaaki Nakamori, a police official in the Nara prefecture in western Japan.

But as he took the test while trying to make sure the examiners didn't get a good look at him, one official noticed that the man looked much older than the picture on the card, Nakamori said.

The father then apologized and confessed. Police said the man runs a company that distributes medicine and had passed an exam in August to earn a license to handle drugs

The man used the ruse because he wanted his son to work alongside him, Nakamori said. The son did not know of his father's intention, he said.

Police expect to charge the man with forging official documents. They are unclear if the man will lose the license he rightfully obtained for himself.