Telescopic shaft for vehicle steering shaft and grease composition for lubricating telescopic shaft

A grease composition which is enclosed in a gap between an outer peripheral portion of a male shaft and an inner peripheral portion of a female shaft of a telescopic shaft for vehicle steering which is installed in a vehicle steering shaft and in which the male shaft and the female shaft are non-rotatably and slidably fitted to each other and the outer peripheral portion of the male shaft and the inner peripheral portion of the female shaft come in contact with each other to transmit a torque during rotation,

• wherein in a base oil which has a kinetic viscosity of 200 mm2/s to 1100 mm2/s at 40° C., a thickener is mixed at a ratio of 5 mass % to 35 mass % relative to a total amount of the grease and an apparent viscosity is ranging from 400 Pa·s to 750 Pa·s (25° C.) at a shear rate of 10 sec−1 as measured in accordance with JIS K2220,
• wherein the base oil is a synthetic hydrocarbon oil, and
• wherein the thickener is at least one of a lithium-based soap and a lithium complex-based soap.