To provide a magnet-built-in lining collar usable as a sweat-absorptive one and a warmth-keeping one so easily detachable to the collar part of a shirt that, in summer, the sweat-absorptive lining collar can be attached to naturally eliminate uncomfortable feeling and thereby kept clean, and that, in winter, the warmth-keeping lining collar can be attached to warm the wearer' s neck part.

This magnet-built-in lining collar usable as a sweat-absorptive one and a warm-keeping one is such one as to have almost the same shape as that of the collar part of a shirt, and formed so that a connecting convex part and a connecting concave part are made to coincide with each other through making the magnet-built-in lining collar usable as a sweat-absorptive one and a warmth-keeping one to be put together inside the collar part of the shirt using a detachable tape. Such an easy detachability mentioned above enables this magnet-built-in lining collar usable as a sweat-absorptive one and a warm-keeping one to be easily exchangeable between respective lining collars as necessary.