Circuit device, electronic device, and cable harness

A circuit device comprising:

• a first bus compliant with a USB standard for connection;
• a second bus compliant with the USB standard for connection;
• a bus switch circuit that, having one end configured to be connected to the first bus and another end configured to be connected to the second bus, switches on connection between the first bus and the second bus in a first period, and switches off the connection in a second period;
• a processing circuit that performs, in the second period, transfer processing for transmitting a packet received from the first bus to the second bus, and transmitting a packet received from the second bus to the first bus;
• and
• a second-bus-side disconnection detection circuit that detects device disconnection of a device connected to the second bus side, wherein
• when device connection of a device connected to the second bus is detected by the second-bus-side disconnection detection circuit, the bus switch circuit, in the second period, switches the connection between the first bus and the second bus from off to on after a wait period has elapsed from a timing at which the device disconnection of device connected to the second bus is detected.