To easily prevent a communication error even in the case that the heights of the light receiving element and light emitting element of two equipments to perform infrared ray communication are different from each other by providing an inclination mechanism capable of adjusting the inclination to a horizontal direction of the light receiving element and/or the light emitting element continuously or stepwise in at least one of the two equipments.

In the case of printing out an arithmetic processing result in a personal computer, when an optional paper feeding cassette is mounted to a printer, the position of the printer, that is the position of the IrDA device 10, becomes high and a prescribed communication condition is not satisfied. In such a case, a dial 24 for inclination adjustment is turned around the rotary shaft 23. Then, since rotation is transmitted through a wheel gear 23 to a horizontal shaft 21 and the IrDA device 10 is rotated around the horizontal shaft 21, the inclination of the IrDA device 10 of the printer and the personal computer is adjusted and the optical axis of the light receiving element 11 of the IrDA device 10 and the optical axis of the light emitting element 12 are made to match.