Pornthep Suvanasarn had been working in the childcare center at the 24 Hour Fitness club in Moraga when he allegedly exposed himself to the two children, a boy and a girl, on March 14, Priebe said.
Suvanasarn had been alone with the children when the incident allegedly happened.
The children told their parents when they picked them up and the parents contacted police, Priebe said.
Suvanasarn was booked into county jail on suspicion of indecent exposure and annoying or molesting children, both misdemeanors.
Priebe noted that although one of the charges mentions molesting children, there is no indication that Suvanasarn touched either of the children.
Suvanasarn was booked into county jail, but posted bail Thursday, a county jail official said.