Child car seat

A child car seat (10) to be to be mounted on a car seat has a child car seat body (10a). The child car seat body (10a) is provided with belt guides (13, 17). The child car seat (10) is mounted on a car seat (25). A seat belt (26) is engaged with the belt guides (13, 17) of the child car seat body (10a) to fasten the child car seat (10) to the car seat (25).