To provide a base station apparatus, mobile communication system and communication control method for enabling appropriate time charging based on actual communication conditions to be performed, the base station apparatus is provided with a connection section that establishes connection with a user equipment (100n), timing sections (2084, 2085, 2011 and 20816) that measure time under charging such that the user equipment (100n) is in a state capable of communicating within a connection period during which the user equipment (100n) is in a connection state, and a charging section (2012) that determines a charging amount based on the time measured by the timing sections (2084, 2085, 2011 and 20816).