To provide a case for a portable cellular telephone which enables absorbing of electromagnetic waves generated from the portable cellular telephone to reduce the discharge of the waves outside and enables carrying of the portable cellular telephone with a longitudinal case put along a waist belt or being inclined slightly upward.

One or two band sheets 10 adequately long to reach both sides 7 and 8 of a case body 1 formed out of a sheet adapted to absorb and shield electromagnetic waves are arranged on the both sides 7 and 8 of the case body 1 crossing over the rear 2 of the case body 1 and are made to separately traverse the rear 2 of the case body 1 at the right angle or askew to the longitudinal direction thereof to fix both ends thereof on the both sides 7 and 8 of the case body 1 or detachably retained thereon with retainers (hooks) 9 and 11. The band sheets 10 are used as belt loop to allow mounting of the case body side ways along the waist belt or being slightly inclined upward.