A photoaffinity-labeled sphingomyelin analog of the following formula: ##STR00001## wherein R.sup.1 is C.sub.1-20 alkylene group, R.sup.5 is C.sub.1-20 alkyl group, aryl group or C.sub.1-6 alkyl group substituted by aryl group, Z is photoaffinity-labeled group and Me is methyl group, or an optically active compound thereof.