The four men were arrested from Nepalgunj airport as they were about to board a domestic airlines' aircraft heading towards Kathmandu, police said.
They have been identified as Layak Ahmed from Delhi, Yakub (30) and Lijanul Haque (21) from Moradabad and Guddu (24) from Baraily, said senior police official Madhu Pudasaini.
The police have recovered 179,500 Euro, USD 2,900 and 1,330 Thai Bhat from them.
Those arrested have confessed that they have been involved in foreign currency racket in the past also.
The police arrested them as they do not have permission to carry the foreign currency.
They said they were supposed to visit Thailand to purchase motor parts.
