A connection test apparatus includes a controlling section, controlling each connection test device to switch the operation mode between the first and the second modes such that a first connection test device among the connection test devices is in the first mode and the remaining connection devices are in the second mode, and controlling a signal generating circuit to output the connection test signal; and a judging section judging, on the basis of the response signal that the first connection test device outputs in response to the connection test signal, a state of connection of a first connector connected to the first connection test device and a first net including the first connector among the nets.