RCMP in Fox Creek say three children were left alone by their parents while the couple went into a house on Saturday afternoon.
Police say the rifle was on the passenger seat and the eldest child fired it out the driver's-side door.
No one was hurt.
A 37-year-old man faces five charges that include unsafe storage of firearms, possession of a restricted firearm and child endangerment.
He is to make his first court appearance on Nov. 24 in Fox Creek provincial court.
Police say they not naming the accused as that could identify the children involved.