The woman, the second wife of a mason, was arrested from her home at Sahachetan house here yesterday after the girl child was found lying on the floor with her limbs bound.
The neighbours had earlier cautioned the child's father about the torture on her and the woman was arrested after an NGO functioning in the locality filed a complaint with the police yesterday.
Chief judicial magistrate Selim Ahmed Ansari sent the woman to jail custody till March 25.
The child has been put under the care of the NGO by the court.
The step-mother, who was pregnant, was often found torturing the child physically and mentally whenever the man was away on work.