The Sheriff's Office says 30-year-old Jaime Mendoza was booked into the Fresno County jail on Monday.
Investigators say the crime happened last Monday and the victim had detailed how Mendoza assaulted her.
"It is disappointing to see one of our own accused of the same type of violent crime that he took an oath to combat," Fresno County Sheriff John Zanoni said in a statement. "I want to ensure the public that we hold our employees accountable just as we do community members, who we contact and arrest for misconduct."
Mendoza has been working with the department since 2016 and was assigned to patrol.
If you are the victim of domestic abuse, or you know someone who is, there is help available 24/7. In Fresno County, call the Marjaree Mason Center at (559) 233-4357. In all other locations, call the National Domestic Violence Hotline at (800) 799-7233.