The gothic-oriented church was built as a hall structure with a massive tower crowned with a pitched roof, shaded from the north and south by two neo-gothic peaks. Following the numerous renovations and conservations, the interior of the temple lost its basic gothic nature. Only the original crystal vault in the vestry was preserved, while the oldest elements of the interior are the Renaissance gravestones located in the south wall of the presbytery. They are the gravestones of the Lębork and Bytowo Starost Joachim Sycewic and his three-year-old daughter Dorota. The Baroque altar from 1702, with the painting of the Crucifixion of Christ expanded with Mary and Mary Magdalene kneeling at the cross, is also notable. An interesting element of the sanctuary is the tabernacle with ivory figure sculptures, relating to the architectural structure of the altar, and the four 18th-Century side altars: St. Anthony’s altar, the retable with the modern painting of Mary stamping on the snake, the altar with the painting presenting Christ’s removal from the cross and the altar dedicated to the Holy Family. Furthermore, there is a valuable pulpit with Rococo forms made from polychrome wood and a polygon canopy crowned with the wooden sculpture of St. James at the north pillar of the main aisle, the first one from the presbytery. The efforts of the Franciscans brought the first-grade relics of James the Apostle to the temple from the Vatican in June of 2010. On 25 July of 2010, under the power of the decree of the Bishop of Pelplin, the church received the title of the Diocesan Sanctuary of St. James.