PURPOSE: To obtain an optical fiber communication device whose signal transfer time is highly stable against a temperature variation by setting a dependability to a temperature of an oscillation wavelength of a light source and a temperature dependability of a signal transfer time of an optical fiber, to a specified relation.

CONSTITUTION: An optical information of a light source 2, which is sent out by an optical transmitting device 1 is transferred to a receiving device 4 through an optical fiber 3. A temperature variation ΔT of the circumference of this optical fiber 3 is detected by a temperature detecting device 6, and given to a temperature control device 7. This temperature control device 7 gives a temperature variation KΔT proportional to a temperature variation ΔT to the light source 2, and controls a temperature of the light source 2. In this respect, a dependability dλ/dT against a temperature T of an oscillation wavelength λ of the light source, a wavelength dispersion value S of the optical fiber in the wavelength λ, and a temperature dependability dτ/dT of a signal transfer time τ of the optical fiber in the wavelength λ sets a value of K so as to satisfy a relation of an equation I . As a result, a variation Δτ=dτ/dTΔT of a transfer time based on the temperature dependability of the optical fiber is negated by a variation Δτ= -S.dλ/dTK.ΔT, and a signal transfer time of a light passing through the optical fiber 3 becomes extremely stable against a temperature.