The man, identified as Raju Banjara, 35, has been arrested, he said.
Raju Banjara was cooking food in his house at Bhagwanpura village when he and his wife picked up an argument as he raised objection over her standing outside last night, Bhanpura police station in-charge Gopal Chouhan said.
The accused also cast aspersions on her character, he said.
Later in a fit of anger, the man flung his son, causing the toddler's death on the spot, Gopal Chouhan said.
The accused was subsequently arrested and booked under IPC section 302 (murder), he added.