To provide an infrared ray communication apparatus for performing two-way infrared ray communication adopting a pulse modulation system wherein a pulse width is constant capable of adjusting the light emission strength of a transmitted infrared ray within a range not causing a communication error at transmission of the two-way communication so as to reduce the power consumption.

The infrared ray communication apparatus includes: a circuit 24 for detecting the number N of signal pulses the pulse width of which is less than a first pulse width among pulses included in a received signal for a prescribed period at reception; and a circuit 27 for detecting the number M of noise pulses the pulse width of which is less than a prescribed second pulse width. When having already received and stored information about a detection result of the number of pulses N, M of an apparatus 13 of a communication opposite party from the apparatus 13 at transmission, a CPU 1 controls a transmission circuit 7 via a transmission control circuit 21 on the basis of the information and adjusts the emission strength of an infrared ray transmitted from a light emitting element 9. Further, the communication apparatus transmits the information about a detection result of the number of pulses N, M of its own apparatus to the opposite apparatus 13.