Lt-Col Andre Traut said the 25-year-old man, a local farmworker, was arrested on Wednesday.
“Crimes against children are regarded our top priority, and we will not relax any of our efforts when a suspect in this regard is sought,” he said.
“We are pleased with the outcome of our investigations so far and would like to extend our appreciation to the Ceres community who assisted us during the recent weeks.”
The baby had been sleeping in bed with her parents when a man snatched and raped her on August 3, provincial police commissioner Arno Lamoer said at the time.
A boy in the same house was also raped.
On Tuesday, the ANC Women’s League said the baby was recovering from her fourth reconstructive surgery operation.
“The rape of these children is not only disheartening, but a horrendous and inhumane act that should be condemned unrelentingly and consistently by all in society,” ANCWL spokeswoman Nosipho Ntwanambi said.
Ntwanambi said the league would continue organising protests calling for men who committed sexual offences to be removed from society.
A 32-year-old man was arrested previously, but released because he could not be linked to the case.