The vendor, Ulas Khan, on a bicycle was asked to stop at a checkpoint outside a courthouse in Mardan district for search but he did not stop, said Dr Mian Muhammad Saeed, District Police Officer Mardan.
He ran in a hurry following which police fired at him on suspicion of being a bomber, he said, adding that he was immediately shifted to a nearby hospital where he succumbed to his injuries. No explosives or weapons was found on his bicycle.
A series of blasts in the Muslim-majority country have killed more than 100 people, including women and children.
Last month, at least seven people were killed and several others, including judges, injured in two separate suicide attacks in Pakistan's restive northwest region.
Also last month, one of the deadliest suicide bombing in Pakistan in recent times struck at the Lal Shahbaz Qalandar shrine in Sehwan area of southern Sindh province where at least 88 people were killed and over 200 injured in an attack claimed by the ISIS.