The museum of Franciscans is in the underground of Franciscans Monastery and it makes up of 3 crypts and the exhibition room

In the exhibition room there is the constant exhibition which shows the Wejher's story and the activity of the monastery in the field of education and Calvary's celebration organization. There are laid prayer books, original clothing, also the scapular, medallion and the comb from Wejher's grave (the town founder), rosary with elaborated furnished beads which comes from the grave of one of Wejher's daughters, the wedding ring of Wejher's second wife and his first wife's, Anna Elżbieta from Schaffogotsch (+ 1665), the cross from XVII century, personal holy medal of Jakub Wejher and medallion from Przebendowski‘s tomb. There is also a document from 5 th March 1651 issued by gnieźnieński's archbishop and given to Jakub Wejher, which states the authenticity of the martyr's St. Leon relics. The relics were taken with the consent of the pope Urban VIII from Rome catacombs. You can also see the liturgical books that were used by first monks in Wejherowo who were brought to town in 1647 by Jakub Wejher.

From the exhibition room there is a corridor to monks' burial crypt. It contains the remains of 57 Franciscans who died in 1658-1809.

The next left crypt is devoted to Wejher's family. In the coffin covered with satin in the cherry-like colour rests Jakub Wejher and next to him his first and second wife as well as his two daughters. The remarkable historic fact is that the remains of the town founder (Jakub Wejher's) rest in the town he founded. It is sensation on Polish as well as European scale. How many town founders rest in the towns they have brought to life?

In the right crypt there rest count Piotr Jerzy Przebendowski (+1755) and his wife Urszula from Potoccy (+1766), the founder of so called Przebendowski's scholarship.