Motor control device and air-conditioning device

A motor control device, comprising:

• an inverter circuit configured to convert a direct-current voltage into an alternating-current voltage, and to supply the alternating-current voltage to a plurality of motors connected in parallel;
• current detectors configured to detect motor currents flowing through the respective motors;
• a relay provided between at least one of the plurality of motors and the inverter circuit and configured to switch an on state and an off state of connection between the one motor and the inverter circuit;
• and
• a controller configured to change number of motors to be driven from the plurality of motors, wherein
• the controller makes a rotation speed of a motor under driving smaller than a rotation speed instruction value when the number of motors to be driven is increased by one, and switches when a monitor rotation speed that is a rotation speed estimated from the motor current detected by the current detector of the motor under driving is less than the rotation speed instruction value, the relay connected to a motor to be activated, from the off state to the on state.